Device and method for chemical analysis

ABSTRACT

Methods and devices for detecting a target agent of interest, e.g., a pathogen, in a sample are described herein. In some embodiments, a sensor is provided that can include a substrate, a graphene layer disposed on a surface of said substrate, and a protein bound to said graphene layer. The protein can be capable of binding to one or more target agents of interest, e.g., pathogens, etc. The binding of the protein to the one or more target agents of interest can generate a change in an electrical property of the graphene layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/538,097, filed Jul. 28, 2017, and U.S. Provisional Application No.62/676,079, filed May 24, 2018. The entire contents of theseapplications are incorporated herein by reference.

BACKGROUND

The present disclosure is directed to methods, systems, and devices foridentifying and quantifying constituents of a sample, e.g., a liquidsample.

A variety of conventional systems are known for analysis of constituentsof a sample. Such conventional systems, however, suffer from a number ofshortcomings. For example, their applicability can be limited, or theycan be expensive or difficult to use.

Accordingly, there is a need for improved systems and methods foranalysis of samples, such as food samples, so as to identify andoptionally quantify one or more of their constituents.

SUMMARY

In various embodiments, a variety of different compounds, and inparticular those that are responsible for the sensation of taste, canmodulate the electrical properties of fullerenes, such as carbonnanotubes, in unique ways. In some embodiments, such modulations of theelectrical properties of fullerenes in response to interaction with avariety of different compounds provide unique signatures of thosecompounds. Those signatures may in turn be used for identifying andquantifying those compounds in a sample, e.g., a liquid sample.

By way of example, the interaction, e.g., contact, of a compound (e.g.,sugar molecules) with a plurality of carbon nanotubes can change the DCelectrical resistance of the nanotubes. Further, the change in the DCelectrical resistance of the carbon nanotubes can be correlated with theconcentration of that compound in a sample.

In other cases, the signature of a compound can be based on the way itsinteraction, e.g., contact, with a plurality of carbon nanotubes, orother fullerenes, can change the AC impedance of the carbon nanotubes.

In some embodiments, a sensor according to the present teachingsexhibits a temporal change in resistance in response to contact with aspecies of interest, where the temporal variation of resistance canuniquely identify that species. For example, in response to contact witha species (e.g., a molecular species), the resistance of the sensor canchange as a function of time in a manner that is indicative of thatspecies. In some cases, a Fourier transform (e.g., a fast Fouriertransform (FFT)) of the resistance of the sensor as a function of timein response to contact with a species can provide the requisiteinformation for identifying that species. In some cases, such temporalvariation of the resistance can be employed to identify multiple speciesthat may be simultaneously present in a sample (e.g., a liquid sample).By way of example, the interaction of certain species with the sensor(e.g., the nanotube mesh of the sensor) can result in a temporalvariation of sensor's resistance that is characterized primarily bylow-frequency components in the Fourier transform spectrum while theinteraction of another species with the sensor may result in a temporalvariation of the sensor's resistance that is characterized primarily byhigh-frequency components in the respective Fourier transform spectrum.In this manner, various species, even when concurrently present in aliquid sample, may be identified and quantified.

In some embodiments, sensing elements comprising fullerenes, such ascarbon nanotubes, are employed to detect selected compounds within aliquid sample, and to determine their respective concentrations. By wayof example, as discussed in more detail below, in some embodiments, aliquid sample can be introduced onto a sensing element, which comprisesa plurality of carbon nanotubes, such that one or more of its molecularconstituents would interact with the carbon nanotubes. The change in oneor more electrical properties of the carbon nanotubes in response totheir interaction with the molecular constituents of the liquid samplecan then be measured. Such electrical properties can include, e.g., DCelectrical resistance, AC electrical impedance, or combinations thereof.For example, in some cases, the change in AC electrical impedance at oneor more AC frequencies can be measured. The changes in the electricalproperties of the carbon nanotubes can then be correlated to thepresence and concentration of selected species (e.g., molecular species)in the liquid sample.

In some cases, the collected data can be compared with calibration datathat had been previously obtained in order to analyze the liquid samplefor the presence and concentration of selected species (e.g., molecularspecies). For example, the response of a sensing element to acalibration liquid sample comprising various concentrations of sugarmolecules (e.g., fructose and/or glucose) in deionized water can bemeasured and stored in a database. Such calibration data can then beemployed to analyze the electrical response of a sensing element to aliquid sample under study to identify and quantify sugar molecules inthat sample. In some cases, the analysis of the sample includes astatistical analysis, such as, principal component analysis, thatemploys the calibration data corresponding to selected molecular speciesas basis vectors to determine concentrations of those species in aliquid sample under study. In some cases, such a database can be storedon a central server to be accessible via the Internet so that variousdevices according to the present teachings can access the database foranalyzing a sample under study.

In some embodiments, one or more filters, e.g., nanofilters, areemployed to segregate different species present in a liquid sample,e.g., based on their molecular weight, mobility, or other properties.For example, in some embodiments in which the detection andquantification of several molecular species in a liquid sample aredesired, a plurality of filters can be employed to segregate thosespecies, if present in the sample, into a plurality of filtrates. Eachfiltrate can then be analyzed, e.g., by employing the fullerene-basedsensors according to the present teachings, to detect the presenceand/or concentration of a respective one of those molecular species.

In some embodiments, a sensor according to the present teachings caninclude a plurality of nanotubes, or other fullerenes, that arefunctionalized by one or more compounds to selectively interact with aspecies (e.g., molecular species) of interest. The modulation of one ormore electrical properties of the functionalized carbon nanotubes inresponse to interaction with a liquid sample can then be predominantlydue to the species of interest. In this manner, the concentration of thespecies (e.g., molecular species) of interest can be extracted. In suchembodiments, the functionalized carbon nanotubes can be viewed aseffectively providing a filtering function, which allows distinguishingthe electrical signal associated with a species of interest fromcontributions of other species in the sample to the modulation of one ormore electrical properties of the carbon nanotubes.

By way of example, a sensor according to the present teachings caninclude carbon nanotubes functionalized to selectively interact withpolysaccharides. This can facilitate detecting and measuring theconcentration of polysaccharides in a liquid sample. Another sensor caninclude carbon nanotubes functionalized with receptors for glutamate toselectively interact with glutamate to facilitate the detection of thisspecies in a liquid sample. In some embodiments, in a device accordingto the present teachings, different groups of sensors can befunctionalized for the detection of different species (e.g., differentmolecular species). In this manner, the device can detect severalspecies. In some cases, such detection can be done in parallel viasimultaneous introduction of sample portions to each of said groups ofsensors.

One application of the present teachings is to determine the “taste” ofa food sample by detecting and quantifying molecular species that areresponsible for the sensation of taste. In some cases, the food samplecan be a liquid sample. In other embodiments, a solid food sample can bedissolved in an appropriate liquid (e.g., water or alcohol) to generatea liquid sample, which can then be analyzed by employing the methods andsystems according to the present teachings.

In one aspect, a device is disclosed that can provide an indication ofthe “taste” of a liquid sample by identifying and quantifying the agentsthat are responsible for the sensation of taste. The sensation of tasteis based on the following basic tastes: sweetness, saltiness, sourness,bitter and umami. Further, certain compounds, such as Capsaicin, whichprovide a sensation of pain, can nonetheless contribute to thesubjective sensation of taste. This sensation is typically referred toas pungency.

For example, as discussed in more detail below, the device can include aplurality of sensors that can be employed in a manner discussed hereinto identify and quantify sugars, salts, acids, glutamates, among otherspecies, present in a liquid food sample. The concentration of thesespecies can then be used to assign a taste, e.g., bittersweet, to thefood sample.

The teachings of the present disclosure can have broad applicability fordetecting and quantifying a variety of organic and inorganic compounds.In some embodiments, the species that contribute to the flavor of a foodsample, such as mint, tarragon, turmeric, ginger, can be identified andquantified in a food sample using the teachings of the presentdisclosure.

In another embodiment, the present teachings can be employed to identifyone or more gluten proteins in a food sample.

Moreover, in some embodiments, a wearable device for chemical analysisof a food sample is disclosed, which comprises a flexible elementconfigured for removably and replaceably mounting onto a body part orclothing of an individual, and an analyzer that is coupled to saidflexible element. The analyzer is configured for removably andreplaceably receiving a cartridge, where the cartridge comprises atleast one sensor configured for detecting one or more chemical speciesin a food sample. By way of example, the flexible element can be a wristband that allows removably and replaceably securing the device to auser's wrist.

The sensor includes one or more sensing elements that can exhibit achange in one or more of their electrical properties in response tointeraction with at least one chemical species of interest. For example,the sensor can include a plurality of carbon nanotubes and/or a graphenelayer, which can exhibit a change in their electrical resistance inresponse to interaction with one or more chemical species in a foodsample.

The analyzer can measure and analyze the change in one or moreelectrical properties of the sensing element(s) of the sensor inresponse to interaction with a food sample to determine if a species ofinterest is present in the food sample (e.g., whether the species ispresent in the food sample at a concentration above a detectionthreshold). By way of example, the analyzer can be configured to comparethe temporal variations of at least one electrical property of thesensing element(s) with one or more calibration curves to determine thepresence of said one or more chemical species in the food sample.

In a related aspect, a system for detecting one or more gluten proteinsin a food sample is disclosed. The system comprises a cartridge forreceiving a food sample, where the cartridge comprises a chamber forreceiving a food sample and a reservoir for containing a process liquid.The food chamber includes an input port for introducing the food sampleinto the chamber and an output port. A frangible barrier separates thefood chamber from the liquid reservoir such that breakage of the barrierallows at least a portion of the liquid stored in the reservoir to flowinto the food chamber. The process liquid extracts at least a portion ofthe food sample to generate a test liquid containing said portion of thefood sample. The cartridge further comprises a sensor, which includesone or more sensing elements positioned relative to the food chamber soas to receive at least a portion of the test liquid. An analyzer incommunication with the sensing element(s) of the sensor measures achange, if any, in one or more electrical properties of the sensingelement(s) and analyzes that change to determine whether a glutenprotein is present in the food sample.

In some embodiments, the sensing element of the sensor comprises agraphene layer functionalized with a plurality of antibody molecules,where the anti-body molecules are capable of selectively binding to agluten protein, such as gliadin.

In some embodiments, a passivation layer covers at least a portion ofthe graphene layer that is not functionalized by the anti-bodymolecules.

In another aspect, a filter is disclosed, which comprises a substrate,and a polymeric material applied to a top surface of the substrate. Insome embodiments, the polymeric material comprises a polymer having thefollowing chemical structure:

In some embodiments, the substrate is porous having a plurality of poreswith sizes in a range of about 1 micrometer to about 100 micrometers. Insome embodiments, the substrate can include a plurality of cellulosefibers. The filter can be both oleophobic and hydrophobic. Such a filtercan have a variety of applications. For example, as discussed in moredetail below, such a filter can be employed in a cartridge in accordancewith the present teachings.

In some embodiments, a wearable device for chemical analysis of a foodsample, the device comprising: a flexible element configured forremovably and replaceably mounting onto a body part or clothing of anindividual; and an analyzer coupled to said flexible element, saidanalyzer being configured for removably and replaceably receiving acartridge, wherein said cartridge comprises at least one sensorconfigured for detecting one or more chemical species in the foodsample.

In some embodiments, said at least one sensor comprises at least onesensing element exhibiting a change in one or more electrical propertiesthereof in response to interaction with said one or more chemicalspecies.

In some embodiments, said analyzer is configured to be in communicationwith said cartridge to detect one or more electrical signals associatedwith said change in the one or more electrical properties of said atleast one sensing element.

In some embodiments, said analyzer is further configured to analyze saidone or more electrical signals to determine presence of said one or morechemical species in said food sample. In some embodiments, said analyzeris configured to compare said one or more electrical signals withcalibration data to determine the presence of said one or more chemicalspecies in the food sample. In some In some embodiments, said at leastone sensing element comprises a plurality of carbon nanotubes. In someembodiments, said at least one sensing element comprises a graphenelayer. In some embodiments, said graphene layer is functionalized with aplurality of antibody molecules. In some embodiments, said flexibleelement comprises a wrist band.

In some embodiments, a system for detecting one or more gluten proteinsin a food sample comprises a cartridge for receiving the food sample,said cartridge comprising: a food chamber for receiving the food sample,said chamber having an input port for introducing the food sampletherein and an output port, a liquid reservoir for containing a processliquid, a frangible barrier separating said food chamber from the liquidreservoir, and a sensor disposed relative to the output port of the foodchamber so as to receive at least a portion of a test liquid exiting thefood chamber, wherein the test liquid is generated via interaction ofthe process liquid and the food sample upon breakage of said frangiblebarrier; and an analyzer in electrical communication with said sensor todetect temporal variation of at least one electrical property of thesensor in response to interaction with said test liquid.

In some embodiments, said sensor comprises a graphene layer and aplurality of antibody molecules coupled to said graphene layer. In someembodiments, said sensor comprises a plurality of carbon nanotubes and aplurality of antibody molecules coupled to said plurality of carbonnanotubes. In some embodiments, said anti-body molecules are capable ofselectively binding to a gluten protein. In some embodiments, saidanti-body molecules are capable of selectively binding to a glutenprotein. In some embodiments, said gluten protein is gliadin. In someembodiments, said gluten protein is gliadin. In some embodiments, thesystem further comprises a passivation layer disposed on at least aportion of said graphene layer not functionalized by said anti-bodymolecules.

In some embodiments, a filter comprises a substrate, a polymericmaterial applied to a top surface of the substrate, wherein saidpolymeric material comprises a polymer having the following chemicalstructure:

In some embodiments, said substrate comprises cellulose fibers. In someembodiments, said filter is oleophobic. In some embodiments, said filteris hydrophilic. In some embodiments, said substrate is porous. In someembodiments, said substrate includes pores with sizes in about 1micrometer to 100 micrometers.

In some embodiments, a system for analyzing a liquid sample comprises atleast one sensor configured to receive the liquid sample, said at leastone sensor comprising a plurality of fullerenes, an analyzer configuredto: measure a change in one or more electrical properties of saidplurality of fullerenes in response to interaction with said liquidsample, and correlate said change to concentration of at least onespecies present in said liquid sample. In some embodiments, saidplurality of fullerenes comprise a plurality of carbon nanotubes In someembodiments, said at least one species comprises at least one proteinassociated with gluten.

In one aspect, a sensor is disclosed, which comprises a substrate, agraphene layer disposed on a surface of said substrate, a protein boundto said graphene layer, wherein said protein is capable of binding toone or more pathogens, and wherein the binding of the protein to saidone or more pathogens generates a change in an electrical property ofthe graphene layer.

The substrate can be, for example, a semiconductor (such as silicon), ora polymeric substrate, such as those discussed above in connection withthe previous embodiments.

In some embodiments, the protein can be a recombinant protein. Theprotein can be coupled, e.g., covalently, to the graphene layer directlyor via a linker. In some embodiments, the protein can be a version ofhuman mannose-binding lectin (MBL).

The binding of one or more pathogens to the protein can modulate atleast one electrical property of the underlying graphene layer, e.g.,its electrical conductance. The detection of such modulation of theelectrical property can in turn allow detection of the pathogen(s) in asample under study. A variety of pathogens, such as, gram-negative andgram-positive bacteria, yeasts and fungi, can be detected. Examples ofsuch pathogens can include Escherichia Coli (E-Coli), Staphylococcusaureus, and Listera in some embodiments.

In some embodiments, the temporal profile of the modulation of at leastone electrical property of the underlying graphene layer in response tothe binding of the protein to one pathogen can be different from therespective temporal profile of the modulation with respect to anotherpathogen. This can allow the detection of that specific pathogen in asample when the sample includes multiple pathogens, each of which canbind to the protein and induce a change in one or more electricalproperties of the underlying graphene layer.

In some embodiments, the at least one electrical property can beelectrical conductance of the graphene layer. Further, in someembodiments the sensor can include a microfluidic delivery devicecoupled to the graphene layer for delivery of a fluid sample thereto.The microfluidic delivery device can include two fluid reservoirs and afluid channel connecting said two reservoirs, and the fluid channel canbe configured such that at least a portion thereof is in fluid contactwith at least a portion of the graphene layer.

In certain embodiments, the sensor can include a reference electrodedisposed in proximity to the graphene layer. In some embodiments, thesensor can further include an AC voltage source for applying an ACvoltage to the reference electrode. The AC voltage source can beconfigured to apply an AC voltage having a frequency in a range of about1 kHz to about 1 MHz in some embodiments. Further, the AC voltage canhave an amplitude in a range of about 1 millivolts to about 3 volts insome embodiments.

In another aspect, a method of detecting a pathogen in a sample isprovided that can include bringing a sample into contact with a graphenelayer functionalized with a protein exhibiting preferential binding to apathogen, as well as applying a time-varying electric field to saidfunctionalized graphene layer. The method can further include monitoringelectrical resistance or another electrical property of said graphenelayer in response to interaction with said sample, and detectingpresence of said pathogen in said sample by detecting a change in saidelectrical resistance or other electrical property indicative ofinteraction of said pathogen with said functionalized graphene layer.

In some embodiments, bringing the sample into contact with the graphenelayer can include delivering sample through a microfluidic structure,said microfluidic structure having at least one reservoir and a fluidicchannel fluidly coupled to said reservoir, said fluid channel being influid communication with at least a portion of said graphene layer, andsaid reservoir being configured for receiving a sample.

In certain embodiments, monitoring electrical resistance of the graphenelayer in response to interaction with the sample can include measuringelectrical resistance of the graphene layer using a pair of conductivepads that are electrically coupled to the graphene layer.

In some embodiments, the method can further include distinguishing thepathogen of interest from among a plurality of pathogens of interest inthe sample based on a temporal profile of modulation of electricalresistance of the graphene layer. In some embodiments, the pathogen cancomprise any of chlamydia trachomatis and Neisseria gonorrhoeae.

Further understanding of various aspects of the embodiments can beobtained by reference to the following detailed description and theassociated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are not necessarily to scale or exhaustive. Instead,emphasis is generally placed upon illustrating the principles of theembodiments described herein. The accompanying drawings, which areincorporated in this specification and constitute a part of it,illustrate several embodiments consistent with the disclosure. Togetherwith the description, the drawings serve to explain the principles ofthe disclosure.

In the drawings:

FIG. 1 schematically depicts a detection system according to anembodiment,

FIG. 2 schematically depicts a cartridge according to an embodiment,

FIG. 3 schematically depicts a cartridge according to anotherembodiment,

FIG. 4A depicts a handheld device according to an embodiment,

FIG. 4B schematically depicts a sensor tip according to an embodiment,

FIG. 5A schematically depicts a sensor device according to anembodiment,

FIG. 5B schematically depicts a sensing element according to anembodiment,

FIG. 6 schematically depicts a device that includes a plurality offilters according to an embodiment,

FIG. 7A schematically depicts an analyzer according to an embodiment,

FIG. 7B schematically depicts a data acquisition module according to anembodiment,

FIG. 8 schematically depicts a data acquisition and analysis systemaccording to an embodiment,

FIG. 9 schematically depicts a display of a GUI employed in a deviceaccording to an embodiment,

FIG. 10 schematically depicts a detection device according to anembodiment,

FIG. 11 schematically depicts a detection device according to anembodiment,

FIG. 12 schematically depicts an exemplary probe station according to anembodiment,

FIG. 13A schematically depicts a detection system according to anembodiment,

FIG. 13B schematically depicts an exemplary implementation of thedetection system with rotatable wheel according to an embodiment,

FIG. 14A is an image of a prototype sensor unit fabricated according tothe present teachings,

FIG. 14B is an image of a four-point probe used for making measurementsshown in FIGS. 15A-15G, according to some embodiments,

FIGS. 15A-15G show exemplary data obtained for a variety of differentcompounds according to some embodiments.

FIGS. 16A and 16B depict a wearable detection device according to anembodiment.

FIGS. 17A and 17B depict a wearable detection device according toanother embodiment.

FIG. 18 depicts a mechanism for securing a cartridge in a cavityaccording to an embodiment.

FIGS. 19 and 20 depict a cartridge according to an embodiment.

FIGS. 21A and 21B depict a sensing element according to an embodiment.

FIGS. 22A-22E depict a sensing element according to an embodiment.

FIG. 23 depicts a cartridge according to an embodiment.

FIGS. 24A-24D, 25, and 26 depict various food grinding mechanismsaccording to different embodiments.

FIGS. 27A and 27B show partial schematic views of a cartridge accordingto an embodiment.

FIGS. 28A-28C, depict views of a cartridge employing a needle accordingto an embodiment.

FIG. 29 depicts a mechanism for triggering a signal to a user accordingto an embodiment.

FIG. 30 is a schematic exploded view of a portion of a cartridgeaccording to an embodiment.

FIGS. 31A and 31B schematically shows an analyzer according to someembodiments.

FIG. 31C shows a graphical user interface according an embodiment.

FIGS. 32A and 32B schematically depict a cartridge that incorporates twosensors according to an embodiment.

FIGS. 33A and 33B show exemplary circuits for measuring electricalresistance of a sensor according to some embodiments.

FIGS. 34A and 34B schematically depict a filter according to anembodiment.

FIG. 35A shows an image of untreated and Nafion-treated GE filters whenexposed to cooking oil.

FIG. 35B shows images of untreated and Nafion-treated GE filters whenexposed to ethanol.

FIG. 35C shows images of untreated and Nafion-treated GE filters whenexposed to deionized (DI) water.

FIGS. 36A-36D schematically depict a food processor according to anembodiment.

FIGS. 37A-37C schematically depict a food processor according to anotherembodiment.

FIGS. 38A-38E show processing and detection systems according to variousembodiments.

FIG. 39 shows some experimental results related to Anti-Gliadin mAblinkage to graphene-coated chips according to an embodiment.

FIGS. 40A and 40B demonstrate effect of Biotinylated-Gliadin Binding aDifferent Concentrations of Ethanol according to an embodiment.

FIGS. 41A and 41B illustrate results of determining a working gliadinconcentration range according to one embodiment.

FIGS. 42A-42B illustrate some effects of ethanol concentration ongliadin binding according to some embodiments.

FIGS. 43A-43B also illustrate some effects of ethanol concentration ongliadin binding from different perspectives according to someembodiments.

FIG. 44 shows results for proof of concept according to an embodiment.

FIGS. 45A-45B show ohmic measurements for, respectively, a nakedgraphene sensor and a graphene sensor functionalized by anti-glutenantibody, according to an embodiment.

FIGS. 46A-46B show ohmic measurements for sensors functionalized withanti-gliadin antibody and those functionalized with mouse monoclonal IgGantibody, according to an embodiment.

FIG. 47A shows measurements for a sensor functionalized by anti-Glutenantibody, and exposed to none-Gluten solution according to anembodiment.

FIG. 47B shows measurements for a sensor covered with Tween 20 andexposed high dosage of Gluten according to an embodiment.

FIG. 48A shows the ohmic behavior of a sensor functionalized by mouseIgG control antibody, exposed to diluted gluten-alcohol solutionaccording to an embodiment.

FIG. 48B shows the ohmic behavior of a sensor functionalized by mouseIgG control antibody, exposed to concentrated gluten-alcohol solutionaccording to an embodiment.

FIG. 48C shows the ohmic behavior of a sensor functionalized byanti-Gluten antibody, exposed to diluted gluten-alcohol solutionaccording to an embodiment.

FIG. 48D shows the ohmic behavior of a sensor functionalized byanti-Gluten antibody, exposed to concentrated gluten-alcohol solutionaccording to an embodiment.

FIG. 49 schematically depicts a sensor according to an embodiment, whichincludes a graphene layer functionalized with a recombinant proteinadapted for binding to a plurality of pathogens.

FIG. 50A is a schematic top view of a sensor system according to anembodiment.

FIG. 50B is a schematic cross-sectional view of the system depicted inFIG. 50A.

FIG. 51 schematically depicts a sensor according to an embodiment, wherethe sensor includes a reference electrode to which an AC voltage can beapplied.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings.The same or similar reference numbers may be used in the drawings or inthe description to refer to the same or similar parts. Also,similarly-named elements may perform similar functions and may besimilarly designed, unless specified otherwise. Details are set forth toprovide an understanding of the described embodiments. The embodimentsmay be practiced without some of these details. In other instances,well-known techniques, procedures, and components have not beendescribed in detail to avoid obscuring the described embodiments.

Summary of Sections

In what follows, section A describes various embodiments of detectionssystems, which detect presence of molecule in a food sample. Section Bdiscloses various embodiments of food grinding systems, which areconfigured to grind or press a food sample, or mix it with a processliquid. Section C discloses filters utilized in various embodiments.Section D discloses various embodiments of processing and detectionsystems, which process a food sample and analyze it to detect a moleculeof interest. And Section E discloses the experimental results for someembodiments.

A. DETECTION SYSTEMS

Some embodiments employ a detection system for detecting presence of amolecule in a food sample.

FIG. 1 schematically depicts a detection system 1 according to anembodiment of the present teachings. System 1 includes a cartridge 10for receiving a sample, e.g., a liquid sample, and an analyzer 12(herein also referred to as a reader unit) that can receive thecartridge to determine the presence and concentration of selectedspecies (e.g., molecular ingredients) in the sample. The analyzer 12 caninclude a display 12 a for presenting the results of the analysis of asample to a user. The results may indicate whether particular species ofinterest are present, and if so, at what concentrations.

The cartridge 10 can include one or more sensors that are configured tointeract with one or more species within a sample. The species may bemolecular or atomic (neutral or charged) species. In many embodiments,the one or more sensors contained in the cartridge include a pluralityof sensing elements. The plurality of sensor elements may include carbonnanotubes, graphene, buckyballs or other fullerenes. In someembodiments, electrical properties, e.g., electrical impedance (such asresistance), of the sensing elements can be modulated in response to aninteraction, e.g., contact, with one or more species present in a liquidsample. The analyzer unit 12 can determine such modulation of theelectrical properties of these sensing elements in response tointeraction with one or more species in a sample. In addition, theanalyzer unit 12 can determine the concentrations of the species viaanalysis of such modulation of the electrical properties of the sensingelement(s).

A liquid sample can be introduced into the cartridge to interact withits sensing element(s) in a variety of different ways. By way ofexample, FIG. 2 schematically depicts an embodiment of a cartridge 10 aaccording to the present teachings. The cartridge 10 a includes amicrofluidic sample delivery component 14 and a sensing component 16.The microfluidic sample delivery component 14 includes an inlet port 18for receiving a liquid sample, and a plurality of microfluidic channels20 a, 20 b, 20 c, 20 d, 20 e, 20 f, and 20 g (herein referred tocollectively as channels 20). Channels 20 can deliver portions of thereceived sample to a plurality of sensing elements 22 disposed in thesensing component 16.

FIG. 3 shows schematics of a cartridge 24 according to anotherembodiment. The cartridge 24 includes a porous top layer 26, and aplurality of sensing elements 22.

Porous top layer 26 provides one or more channels 26 a. When a liquidsample is disposed on the exposed surface of the porous layer 26, thechannels 26 a guide the liquid to sensing elements 22. In someembodiments, the porous layer 26 may be formed of polymeric materialssuch as porous polyurethane.

FIG. 4A schematically depicts a handheld device 100 according to anembodiment of the present teachings. Device 100 includes a sensor tip130 and an analyzer 132, which is in communication with sensor tip 130.While in this embodiment the sensor tip 130 and the analyzer 132 areformed as one integral unit, in other embodiments the sensor tip 130 andthe analyzer 132 can be formed as separate devices that communicate withone another. For example, in some embodiments, the sensor tip 130 cantransmit data obtained regarding a sample of interest to the analyzer132 via a wired or wireless connection. In some such embodiments, thesensor tip 130 can communicate with the analyzer 132 wirelessly, e.g.,via a plurality of different wireless protocols such as Bluetooth, IEEE802.11, etc.

In various embodiments, the device 100 can have a variety of differentsizes based on the application. By way of example, the device 100 canhave a length in a range of about 2 to about 4 inches, and a width in arange of about 0.25 to about 0.5 inches.

FIG. 4B further shows a sensor tip according to an embodiment. Thesensor tip shown in FIG. 4B includes a plurality of sensing elements140.

In use, the tip can be exposed to a liquid sample. For example, the tipcan be dipped into the liquid sample to draw at least a portion of thesample into the device so as to contact one or more of the sensingelements 140. The sensing elements 140 can then provide signalsindicative of the presence and concentration of various species, e.g.,molecular species, in the liquid sample. The analyzer 132 can thenutilize these measurements in a manner described herein to identify andquantify those species.

In various embodiments of the present teachings, sensing elements basedon fullerenes, e.g., carbon nanotubes, are employed to detect andquantify selected species within a liquid sample. FIG. 5A schematicallydepicts a sensing device 200 according to an embodiment. Sensing device200 has a plurality of sensing elements 201. The sensing elements 201are disposed on an underlying substrate. A variety of materials can beemployed for forming the underlying substrate. By way of example, theunderlying substrate 202 can include one or more of silicon,silicon-on-insulator (SIMOX) or a variety of other substrates. In theembodiment shown in FIG. 5A, for example, sensing device 200 has anunderlying substrate that includes a silicon substrate 202 a with a thinsilicon dioxide layer 202 b separating the sensing elements 201 from thesilicon substrate 202 a.

FIG. 5B shows schematics of a sensing element 201 according to someembodiments. Sensing element 201 comprises a plurality of carbonnanotubes 210 (e.g., a mesh of carbon nanotubes) that are disposed onthe underlying substrate. Carbon nanotubes 210 extend from a proximalend (PE) to a distal end (DE). In some embodiments, the majority of thecarbon nanotubes 210 (and in some cases all of those carbon nanotubes)are single-walled carbon nanotubes (SWCNTs). Some other embodiments usemulti-walled carbon nanotubes, or a combination of single-walled andmulti-walled carbon nanotubes. In some embodiments, the carbon nanotubescan have a length in a range of 100 nm to about 20 mm.

In FIG. 5B, sensing element 201 includes electrically conductive pads240 and 242. In particular, two electrically conductive pads 240 a and240 b are electrically coupled to the proximal end of the carbonnanotubes 210. Two other electrically conductive pads 242 a and 242 bare electrically coupled to the distal end of the carbon nanotubes 210.These pads can allow measuring the impedance of the carbon nanotubes,e.g., the DC electrical resistance of a mesh of carbon nanotubes formedby the plurality of carbon nanotubes 210. By way of example, a currentsource can be employed to cause the flow of a known current through thecarbon nanotubes of a sensor via these pads, and a voltage generatedacross the carbon nanotubes in response to the current can then bemeasured. The voltage can be measured via electrical connections of theprobes of a voltage measuring device with the electrical pads of asensor. Such measurements in response to contact of a sample with thecarbon nanotubes of a sensor can be employed to identify and quantifyselected species within a liquid sample.

In some embodiments, the carbon nanotubes, or other fullerenes, of asensor can be functionalized so that they can selectively interact witha species of interest, e.g., a molecular species. By way of example, thecarbon nanotubes can be functionalized with receptors for glutamate sothat the carbon nanotubes can selectively interact with glutamate withina liquid sample.

In some embodiments, a plurality of filters, e.g., nanofilters, can beemployed. The filter can be employed to segregate selected species in aliquid sample from other constituents of the sample and to guide thosespecies to the sensing elements of a device according to the presentteachings. By way of example, FIG. 6 schematically depicts such anembodiment. In FIG. 6, a plurality of filters (e.g., nanofilters) 40 a,40 b, 40 c, 40 d, 40 e, and 40 f (herein collectively referred to asnanofilters 40) are configured to receive a liquid sample via amicrofluidic device 41. More specifically, a sample can be delivered tothe fluidic device 41 via an input port 41 a thereof. The microfluidicdevice can then distribute a portion of the sample to each of thenanofilters 40. The passage of the sample portions through thenanofilters may result in a plurality of filtrates, where each filtrateis guided to a selected group of a plurality of sensing elements 44. Inthis example, the filtrate generated by the nanofilter 40 a is guided tosensors 44 a, 44 b, 44 c, and 44 d; and the filtrate generated by thenanofilter 40 b is guided to the sensing elements 44 e, 44 f, 44 g, and44 h. The filtration can be performed based on a variety of differentcriteria, e.g., molecular weight, mobility, etc. By way of example, oneof the nanofilters can segregate sugar molecules from the sample whileanother can segregate glutamate from the sample. In some embodiments,one or more of the filters can be implemented as liquid chromatographycolumns (i.e., LC columns).

FIG. 7A shows the analyzer 12 according to some embodiments. Theanalyzer 12 may include a data acquisition unit (herein also referred toas a measurement unit) 700, an analysis module 1700.

The analyzer 12 may further include other components, such as amicroprocessor 1702, a bus 1704, a Random Access Memory (RAM) 1706, aGraphical User Interface (GUI) 1708 and a database storage device 1712.The bus 1704 may allow communication among the different components ofthe analyzer 12. In some embodiments, the analysis module can beimplemented in the form of a plurality of instructions stored in the RAM1706. In other embodiments, it can be implemented as dedicated hardwarefor performing processing of data obtained by the data acquisition unit700.

Data acquisition unit 700 may be configured to acquire electrical datafrom which one or more electrical properties of a sensor (e.g., its DCresistance) can be determined. In this embodiment, the data acquisitionunit includes a current source 700 a for supplying electrical currentsof selected values to the sensing elements (e.g., to the carbonnanotubes of the sensing elements) and a voltage measuring circuit 700 bthat can measure the voltage across each of the sensing elements, e.g.,across the carbon nanotubes of each sensing element.

FIG. 7B schematically depicts a voltage measurement circuitry 701according to some embodiments. Voltage measurement circuitry 701 can beemployed as the measurement unit 700 for measuring electrical resistanceof a sensor, e.g., sensor 702 that is depicted in this figure as anequivalent circuit diagram of a sensor according to the presentteachings. A fixed voltage V (e.g., 1.2 V) is generated at the output ofa buffer operational amplifier 703. This voltage is applied to one input(A) of a downstream operational amplifier 704 whose other input B iscoupled to VR1 ground via a resister R1. The output of the operationalamplifier 704 (Vout1) is coupled to one end of the sensor 702 and thenon-connected to VR1 end of the resistor R1 is coupled to the other endof the sensor 702 (in this schematic diagram, resistor R2 denotes theresistance between two electrode pads at one end of a sensor, resisterR3 denotes the resistance of the nanotubes of a sensor extending betweentwo inner electrode pads of the sensor, and resistor R4 denotes theresistance between two electrode pads at the other end of the sensor).As the operational amplifier maintains the voltage at the non-connectedto VR1 end of the resistor R1 at the fixed voltage applied to its input(A), e.g., 1.2 V, a constant current source is generated that provides aconstant current flow through the sensor 702 and returns to ground viathe resistor R1 and VR1.

The voltage generated across the nanotubes of the sensor is measured viathe two inner electrodes of the sensor. Specifically, one pair of theinner electrode pads is coupled to a buffer operational amplifier 706and the other pair is coupled to the other buffer operational amplifier708. The outputs of the buffer operational amplifiers are applied to theinput ports of a differential amplifier 710 whose output port providesthe voltage difference across the carbon nanotubes of the sensor. Thisvoltage difference (Vout1_GLO) can then be used to measure theresistance exhibited by the sensor. The current forced through R3 is setby I=(Vref−VR1)/R1. The value of VR1 is digitally controlled. For eachvalue of current I, the corresponding voltage (Vout1_GLO) is measuredand stored. The resistance of the sensor may be different at any givencurrent so it is calculated as derivative of voltage, Vout1_GLO, withrespect to current I, i.e., R=dV/dI≈ΔV/ΔI using the stored voltageversus I. If the sensor has linear constant resistance, the value of Rcan be found as R=dV/dI=ΔV/ΔI=V/I.

Referring back to FIG. 7A, the analysis module 1700 can be configured toreceive the current and voltage values generated and obtained by themeasurement unit 700 and can process these values according to thepresent teachings. The analysis may identify and quantify selectedspecies, e.g., molecular species, present in a liquid sample. Differentunits in the analyzer 12, as well as other units of the analysis module,can operate under the control of the microprocessor 1702.

By way of example, as discussed in more detail below, in some cases, theanalysis of a liquid sample is directed to the identification andquantification of the species that are primarily responsible for the“taste” of a liquid food sample.

For example, in some embodiments, the analysis unit employs the valuesof currents and voltages that it receives from the measurement unit fora sensor and calculates the change in one or more electrical propertiesof the carbon nanotubes (or other sensing elements) of that sensor inresponse to interaction with a liquid sample. For example, the analysismodule can calculate a change in the DC electrical resistance and/or ACelectrical impedance of the carbon nanotubes. The change can becalculated relative to calibrated values of such electrical propertiesobtained in absence of the liquid sample. The calibration can be doneonce or can be performed for each measurement session.

The analysis module can then correlate the calculated change in one ormore electrical properties of the sensor, exhibited in response tointeraction of the liquid sample, with a particular species of interestin the sample. For example, the analysis unit can utilize the calculatedchange in one or more electrical properties of the sensor to identifyand quantify sugar molecules in the sample. By way of example, theanalysis unit can compare the change in the electrical properties with aplurality of calibrated values of change previously obtained forselected species, e.g., polysaccharides and stored in a database 1712,to determine whether a particular species is present in the sample, andif so, at what concentration.

While in some embodiments, the various functional modules or componentsof, the analyzer 12, such as the analysis module 1700, and the database1712 can be integrated within a single device, in other embodiments, oneor more of the modules, e.g., the analysis module 1700 and/or thedatabase 1712, can be provided on a server (e.g., remote server), whichcan communicate other modules of the analyzer via a network, e.g., theInternet.

By way of example, FIG. 8 schematically depicts a data acquisition andanalysis system according to an embodiment. The system of FIG. 8includes a device 800 that comprises a data acquisition module 800 a forreceiving electrical data from a sensor according to the presentteachings (not shown in this figure). Device 800 has a network interface800 b. Moreover, the system of FIG. 8 includes a network 802, e.g., theInternet. Through network interface 800 b and network 802, device 800communicates with a server 804. Server 804 may have an analysis module,which can receive the data transmitted by the device 800, process thatdata according to the present teachings, and transmit the analysisresults back to the device 800.

With reference to FIG. 9, in some embodiments, such a device 800 caninclude a graphical user interface (GUI) 900 for displaying the analysisresults to a user. Alternatively or in addition, the server 804 cantransmit the analysis results to a user's mobile device that executes anapplication for presenting the analysis results to a user.

In some embodiments, the analysis results generated by the analysis unitcan be stored in a database, such as database 1712 of FIG. 7A, oranother database. In some embodiments, the database can storecalibration data regarding the signature of certain compounds obtainedby employing the teachings of the present disclosure. For example, insome embodiments, the modulation of one or more electrical properties(e.g., DC electrical resistance) of a sensing element according to thepresent teachings in response to contact with a species (e.g., glucosemolecules) can be obtained and stored in the database as the signatureof glucose. This signature can then be utilized for identifying andquantifying glucose molecules in a sample under study.

As noted above, in some embodiments, the sensors can comprise multiplegroups, where one group is configured, e.g., via functionalization, tobe primarily sensitive to one, or several, molecular species. Forexample, a group of sensors can be configured to be primarily sensitiveto polysaccharides. In such a case, the measurement module can transmitthe measured results together with information indicating the sensor (orsensors) from which the results were obtained to the analysis module.

As noted above, in some embodiments, the present teachings are employedto determine the “taste” of a liquid food sample. In such embodiments,the analysis module is configured to identify and quantify the speciesthat are primarily responsible for the sensation of taste. In someembodiments, the analysis module can be further configured to assign a“taste score” to the liquid sample based on calculated concentrations ofthese species.

The five basic tastes comprise sweetness, bitterness (or pungency),saltiness, sourness, and umami. Although pungency is a heat sensation,rather than a taste sensation, it is typically included in the fivebasic tastes due to its importance in the subjective sensation of taste.Table 1 below lists a number of chemical compounds that can contributeto the sensation of particular taste

TABLE 1 Item Taste Material Natural Source 1 Pungency Capsacin Pepper 2Sweetness Glucose Fruits, Sugar, Drinks 3 Fructose Fruits 4 SucroseSugar 5 Umami Glutamic acid Meat, Soy sauce 6 Saltiness Sodium chlorideSalt 7 Potassium chloride Synthetic salt 8 Sourness Acetic acid Vinegar9 Citric acid Lemon juice 10 Malic acid

In some embodiments, a device according to the present teachings candetect and quantify the above compounds in a sample, e.g., food sample,according to the present teachings.

The teachings of the disclosure are not limited to the embodimentsdiscussed above, but can be implemented in a variety of different ways.For example, with reference to FIG. 10, in another embodiment, adetection device according to the teachings of the disclosure can be inthe form of a spoon 1000 having a bowl portion 1002 and a handle 1004extending from the bowl portion 1002. The bowl portion provides adepression configured to receive a liquid sample. A plurality of sensors1006 according to the present teachings can be incorporated in the bowlportion 1002. In this embodiment, the sensors 1006 are incorporated inthe bowl portion substantially in proximity of its tip. In otherembodiments, the sensors can be distributed differently along the bowlportion. The sensors 1006 are in communication with an analyzer (notshown), which is incorporated in the handle 1004. The analyzer isconfigured to receive data (such as electrical data) from the sensors inresponse to the interaction (e.g., contact) of the sensors with specieswithin the liquid sample received in the bowl portion. The analyzer cananalyze, e.g., in a manner discussed above in connection with analyzer12, the received data in order to identify and quantify selected specieswithin the liquid sample. In this embodiment, the spoon 1000 includes aGUI having a display 1008 incorporated within the handle 1004, which canpresent the results of the analysis of the liquid sample to a user. Forexample, the GUI can display the concentration of selected species inthe liquid sample, e.g., one or more species responsible for the tasteof a liquid sample, to a user.

FIG. 11 schematically presents yet another embodiment of a detectiondevice 1100 according to the present teachings. The device 1100 includesa container 1101 (e.g., a vial) for receiving a liquid sample. Thedevice 1100 further includes a cap 1102 and an arm 1104, which extendsfrom a proximal end, coupled to the cap, to a distal end at which aplurality of sensors 1106 is disposed. The cap 1102 can engage with thecontainer so as to place the sensors within the liquid sample. In someembodiments, a measurement module, such as the measurement modulediscussed above, can be incorporated in the cap, which can measure theresponse of the sensors to one or more species in the liquid sample. Insome embodiments, a plurality of transmission media (e.g., wires) canextend from the sensors to the measurement unit to transfer electricaldata thereto. In some embodiments, such transmission media can bedisposed on the surface of the arm 1104, or alternatively, incorporatedwithin an internal channel provided in the arm extending from thesensors to the measurement unit.

In some embodiments, a communications interface (e.g., a wirelesscommunication interface) incorporated in the cap 1102 can transmit themeasurement data to a remote analysis unit (e.g., a remote server suchas that shown in FIG. 8 for analysis). As discussed above, in someembodiments, the analysis unit can be running on a remote server.Alternatively, the analysis unit can be incorporated in the cap 1102 soas to operate on the measurement data generated by the measurement unit.A display 1008 incorporated operated by a GUI can present the analysisresults to a user.

A plurality of materials and techniques can be employed to fabricate asensor according to the present teachings. In one approach, a thinsilicon dioxide (SiO₂) layer (e.g., a layer having a thickness in arange of about 100 nm to about 200 nm) can be formed on an underlyingsilicon substrate (e.g., via thermal oxidation). Subsequently, grapheneand/or carbon nanotubes can be printed onto the silicon dioxide layer.On each end of the printed line, one or more (typically two) metalelectrodes can be formed (e.g., via vapor deposition) to facilitateelectrical coupling to the carbon nanotube mesh and/or graphene layers.In some embodiments, a plurality of such sensors can be formed on theunderlying substrate.

In some embodiments, the fullerene-based sensing element of a sensoraccording to the present teachings can be formed by depositing a layerof graphene oxide on an underlying substrate, e.g., a SiO₂ coatedsilicon substrate. The graphene oxide layer can then be exposed toradiation to form a graphene layer.

In one application, the teachings of the present teachings can beemployed to detect and quantify gluten in a food sample. It is known inthe art that gluten is a protein composite that can be found in wheat orother grains, such as barley and rye. As the number of individuals withgluten allergy increases, especially in North America, there is anincreased interest in reliable and efficient methods for detectinggluten in food samples. In general, gluten refers to a family ofcomposite proteins, which includes primarily Prolamins and Glutenins. Inmany food samples, these two categories of storage proteins are bindedby starch molecular strands. The proteins in the Prolamins categoryinclude gliadin (wheat), hordein (barley), secalin (rye), zein (corn),kaffrin (sorghum), and avanin (oat). The molecular weight of theseproteins varies from about 10 KDa to about 90 KDa.

In some embodiments, one or more of these proteins are identified, andoptionally quantified, in a food sample. In some such embodiments, thefood sample is dissolved in an alcohol (e.g., ethanol) and the alcoholsolution is passed through one or more filters (e.g., micro liquidchromatography columns) to generate a filtrate containing one or more ofthe above gluten proteins. The filtrate is then allowed to contact witha sensing element according to the present teachings. The change in anelectric property of the sensing element (e.g., the DC resistance and/orAC impedance of the carbon nanotubes of the sensing element) is measuredand analyzed to determine whether one or more of the above glutenproteins are present in the food sample. By way of example, a temporalvariation of DC resistance of the sensing element can be analyzed byreference to previously-determined respective responses of the sensingelement to all or a subset of the above gluten proteins to identify oneor more of these proteins in a food sample. A Principal ComponentsAnalysis (PCA) in which the previously-determined responses are employedas the basis vectors can be employed to identify (and optionallyquantify) one or more of the above gluten proteins in a food sample.

In some embodiments, the fullerenes (e.g., carbon nanotubes) of asensing element can be functionalized with an antibody that canselectively bind to one of the above gluten proteins. When a liquidsample (e.g., a sample of food dissolved in alcohol) is introduced toonto the sensing element, the gluten protein that can selectively bindto the functionalized fullerenes (e.g., functionalized carbon nanotubes)via the antibody. Such binding of the protein to the functionalizedcarbon nanotubes (or other fullerenes) of the sensing element can modifyone or more electrical properties (e.g., DC resistance) of thefunctionalized carbon nanotubes. The change in the electrical propertyof the carbon nanotubes can then be detected and analyzed to determinethe presence of that protein in the food sample. By way of example, thecarbon nanotubes of a sensing element can be functionalized with G12antibodies, which can selectively bind to gliadin protein, e.g., 33-merof the gliadin protein (hexapeptide sequence QPQLPY), and similarpeptides in the Prolamins. In some embodiments, different groups ofsensing elements are functionalized with different antibodies, whereeach antibody can bind to a different one (or a different group) of theabove gluten antibodies. In this manner, in some embodiments, a deviceaccording to the present teachings can detect concurrently a pluralityof different gluten proteins present in a food sample.

By way of further illustration, FIG. 13A schematically depicts adetection system 1300 according to another embodiment. System 1300includes an analyzer 1301 and a plurality of cartridges 1302 a, 1302 b,1302 c, 1302 d, etc. (herein referred to collectively as cartridges1302). Each of the cartridges 1302 includes one or more sensing elements(such as sensing element 1303 a, 1303 b, 1303 c, 1303 d, etc.), such asthose discussed above. The sensing element may be further configured(for example, via functionalization or otherwise) to be primarilyresponsive to a particular species of interest. For example, in thisembodiment, the cartridge 1302 a can be used to detect (and optionallyquantify) gluten in a sample while the cartridges 1302 b, 1302 c and1302 d can be utilized, respectively, for detecting sugar, salt, umami,etc.

In use, a sample (e.g., a liquid sample) can be introduced into one ofthe cartridges 1302 (e.g., using one of the methods discussed above).The cartridge can then be removably coupled to the analyzer 1301 (e.g.,via an inlet) to identify and optionally quantify (if present) thespecies of interest.

FIG. 13B schematically depicts an exemplary implementation of thedetection system 1300 according to another embodiments. In FIG. 13B, thecartridges 1302 are arranged as a wheel 1304 that can be rotatablycoupled to the analyzer 1301. By rotating the wheel one or more of thecartridges 1302 onto which one or more samples under study have beenintroduced can be coupled into the analyzer 1301. The analyzer 1301 canthen interrogate the sensing elements of the one or more cartridges,e.g., in a manner discussed above in connection with the previousembodiments, to identify and optionally quantify the species ofinterest.

The following Examples are provided for further illustration of variousaspects of the present teachings and are not intended to necessarilyindicate the optimal ways of practicing the disclosure or the optimalresults that can be obtained.

EXAMPLES

FIG.14A shows an image of a prototype sensor unit according to thepresent teachings. The sensor unit includes a plurality of sensors(herein also referred to as sensing elements) according to the presentteachings that are disposed on an underlying silicon substrate. A layerof silicon dioxide is present between the underlying substrate and thesensors. Each sensor comprises a plurality of single walled carbonnanotubes, which form a mesh and extend between two pairs of metal pads,which can be used for measuring electrical properties of the nanotubesas discussed below.

Each sensor was fabricated by coating the substrate withmono/multi-layer carbon nanotubes (SWCNT) with a thickness of 20 micronsand a maximum line length of 20 mm. Specifically, for each sensor, theCNT layers were printed as a line on the underlying silicon oxidecoating of the silicon wafer. On both ends of the printed line, twoelectrodes of Chromium/Palladium (Cr/Pd) were formed by vapor depositionmethod to facilitate measuring the electrical resistance of the printednanostructures in response to exposure to a number of chemicalcompounds. The thickness of the Cr/Pd electrodes was about 150 nm.

More specifically, a silicon dioxide layer was formed in a siliconsubstrate by oxidizing the substrate. A photoresist layer was thendeposited on the silicon oxide layer. The deposited photoresist layerwas then patterned. Metal was then deposited on the patterned layer toform the aforementioned metal electrodes. The photoresist was thenremoved (washed). Carbon nanotubes were then printed as one or morelines between the metal electrodes to generate a plurality of sensors.Subsequently, another photoresist layer was spin-coated on the substrateand then patterned to provide circular access ports to the carbonnanotubes of each sensor.

The four point measurement method was used for performing resistancemeasurements in order to eliminate the effects of contact resistancesand wire resistances. FIG. 14B shows a four-point probe that wasemployed to measure the electrical characteristics of the sensingelements of the sensor unit shown in FIG. 14A.

For measurement consistency, a layer of a photoresist material was addedto the assembly via spin coating to avoid any electrical short contactsand to limit the exposure of chemical solutions under study to theaccess circle of 2 mm diameter.

A customized probe station was designed and assembled to facilitateperforming the measurements on the specific pattern of the sensors onthe underlying wafer. As shown in FIG. 12, the probe station included aplatform 1201 for mounting the substrate via vacuum suction. The probestation further included a plurality of multi-contact DC probes 1202that were coupled to an arm 1203. The arm 1203 in turn was attached toan xyz translation stage 1204 to allow positioning the probes inregister with a desired sensor. To perform electrical measurements, theDC probes were then brought into Ohmic contact with the respective padelectrodes.

FIG. 15A-15G show graphs of data collected for the performance of thesensing elements according to some embodiments. The graphs show datacorresponding to temporal changes in the DC resistance of sensingelements of the prototype sensor unit when exposed to a plurality ofdifferent compounds. In the graphs, the horizontal axis shows time andthe vertical axis show relative change in resistance (ΔR/R₀) measured inpercentage. Specifically, FIG. 15A shows the change in the resistance ofa sensing element as a function of time when an aqueous solution ofsodium chloride with an approximate molarity of 1 was introduced to thesensing element. FIG. 15B shows resistance data obtained by introducingan aqueous solution of capsaicin at an approximate molarity of 6.5×10⁻⁵to another sensing element. FIG. 15C shows resistance data obtained byintroducing an aqueous solution of fructose at an approximate molarityof 1 to a sensing element. FIG. 15D shows resistance data obtained byintroducing an aqueous solution of sucrose at an approximate molarity of1 to a sensing element. FIG. 15E shows resistance data obtained byintroducing an aqueous solution of glucose at an approximate molarity of1 to a sensing element. FIG. 15F shows resistance data obtained byintroducing an aqueous solution of glutamic acid at an approximatemolarity of 6.8 to a sensing element. FIG. 15G shows resistance dataobtained by introducing an aqueous solution of citric acid at anapproximate molarity of 1 to a sensing element. Table 2 shows in moredetail the specifics of the solutions used to derive the data shown inFIGS. 15A-15G.

TABLE 2 Molecular Mass Volume Weight g/mol ml g Molar Sodium Chloride58.44 5 0.2922 1 Capsasin 305.41 50 0.001 6.54857E−05 Fructose 180.16 50.9008 1 Sucrose 342.2965 5 1.71148 0.999998539 Glucose 180.1559 50.90078 1 Glutamic Acid 147.13 5 5 6.796710392 Citric Acid 192.12 50.9606 1

The above data indicates that, according to some embodiments, theinteraction of the tested compounds with the sensing elements providesunique signatures for identifying the compounds. In particular, thetemporal variation of the resistance exhibited for one compound isdifferent from the respective temporal variation exhibited for anothercompound. Such differences can be employed to uniquely identify thecompounds in a sample under study. For example, in some embodiments,such analysis can be facilitated by obtaining the Fourier transform ofthe time variation of resistance of each compound. The Fourier transformcan provide unique spectral signatures for the compounds.

In some embodiments, a device according to the present teachings can beimplemented as a wearable device that can be removably and replaceablyattached to a body part or clothing.

By way of example, FIG. 16A depicts a wearable detection device 1600according to an embodiment of the present teachings for chemicalanalysis of a food sample. The device 1600 includes a flexible member1602 in the form of a wrist band that allows a user to wear the devicesimilar to a watch. The wrist band includes a fastening element 1604,e.g., a clip or a hook-and-loop element, for removably and replaceablysecuring it to a user's wrist. The wrist band can be made of a varietyof different materials such as leather, plastic, etc.

The wearable device 1600 includes an analyzer 1606 that is mechanicallycoupled to the wrist band. As discussed in more detail below, theanalyzer 1606 can be used to determine whether a chemical species ofinterest is present in a sample, e.g., a food sample, and optionallyquantify the concentration of that species in the food sample.

In other embodiments, a wearable device according to the presentteachings can be secured to another body part, e.g., a user's arm, oreven to a user's clothing. By way of example, FIGS. 17A and 17Bschematically depict a wearable detection device 1700 according toanother embodiment. Device 1700 includes an analyzer 1702 for analyzinga food sample, e.g., in a manner discussed below. Device 1700 furtherincludes a clip 1704 for removably and replaceably securing device 1700to clothing or other places. In this embodiment, the analyzer 1702includes a display 1706 for presenting the results of the food analysisto a user.

Referring back to FIG. 16A, the exemplary analyzer 1606 includes a lid1606 a that is hingedly coupled to a casing 1606 b. A user can open thelid 1606 a to access a cavity 1608 provided in the casing 1606 b withinwhich a cartridge, such as cartridge 1900 shown in FIG. 19, can beremovably and replaceably engaged. The casing 1606 b further provideshousing for circuity adapted to receive and analyze electrical signals.The electrical signals may be associated with a change in one or moreelectrical properties of one or more sensors that are disposed in thecartridge. The change may result in response to interaction with a foodsample, as further discussed in more detail below.

As shown in FIG. 16B, in this embodiment, the analyzer 1606 includes adisplay 1610 in the analyzer's lid, which can present the results of achemical analysis of a food sample to a user. In other embodiments, theanalyzer may not include such a display. Rather, the analyzer can sendthe results of chemical analysis of a food sample to a user's device,e.g., a mobile device, for presentation to the user.

More specifically, the cartridge 1900 can be inserted into the cavity1608 of the analyzer 1606 via an aperture 1608 a thereof and secured inplace via a plurality of mechanisms. One example of such a mechanism isdepicted with reference to FIG. 18. As the cartridge 1900 is advanced inthe cavity 1608, it pushes against a spring 1611 provided in the distalend of the cavity. Moreover, a pin 1609 in a sidewall of the cavity 1608can engage with a notch 1900 a provided on a side surface of thecartridge 1900 to secure the cartridge 1900 in place.

Other mechanisms can also be employed for securely engaging thecartridge within the cavity. For example, in some embodiments the cavitycan include a plurality of protruding spring-loaded pins (not shown).The bottom surface of the cartridge can, in turn, include a plurality ofreceptacles (sockets) for engaging with the pins when the cartridge isdisposed within the cavity.

Referring again to FIG. 16A, a tab or a button 1612 provided in thecasing can be utilized to disengage the pin from the notch, therebyreleasing the cartridge for removal from the cavity. More specifically,in order to remove the cartridge from the cavity, a user can open theanalyzer's lid 1606 a and use the tab to disengage the cartridge fromthe analyzer. Other mechanisms known to those skilled in the art canalso be used to removably and replaceably disengage the cartridge 1900from the analyzer 1606.

As shown schematically in FIG. 19, the cartridge 1900 can include aprotective peelable layer 1901 (herein also referred to as a protectivecover). As discussed in more detail below, the protective layer 1901 canbe partially peeled off to allow access to a chamber in the cartridgethat is adapted for receiving a food sample. Subsequently, theprotective layer can be reapplied to seal the food chamber prior toinserting the cartridge into the analyzer. By way of example, theprotective layer 1901 can be formed of a flexible polymeric material,such as polyurethane, or polymethyl methacrylate. A tab 1901 a canfacilitate peeling off the protective layer partially or completely.

With reference to FIG. 20, the exemplary cartridge 1900 includes asensor 2000. Sensor 200 comprises one or more sensing element(s) 2002for detecting and optionally quantifying one or more chemical species ofinterest, such as one or more gluten proteins, in a food sample. By wayof example, the sensor 2000 can be one of the sensors discussed above inconnection with the previous embodiments for generating electricalsignals in response to interaction with one or more chemical species ofinterest. In some embodiments, the sensing element of the sensor caninclude a graphene layer. A plurality of metal pads 2004 a, 2004 b, 2004c, and 2004 d (herein collectively referred to as metal pads 2004) allowreading one or more electrical signals associated with a change in atleast one electrical property of the graphene layer in response tointeraction with one or more chemical species. In this embodiment, aplurality of electrical connections 2006 a, 2006 b, 2006 c, and 2006 delectrically couple the metal pads 2004 a, 2004 b, 2004 c, and 2004 d,respectively, to elongated conductive paths 2008 a, 2008 b, 2008 c, and2008 d, which terminate in electrical pads 2010 a, 2010 b, 2010 c, and2010 d (herein referred to collectively as “electrical pads 2010”),respectively.

As discussed in more detail below, the analyzer can detect theelectrical signals associated with a change in at least one electricalproperty of the sensing elements via the electrical pads 2010 (and insome embodiments via the electrical pads 2010 and vias connecting thepads to a data acquisition circuitry of the analyzer) and analyze them,e.g., in a manner discussed above in connection with the previousembodiments and further elucidated below. The analysis can determine thepresence, and optionally the concentration, of an analyte of interest ina food sample. In some embodiments, a plurality of carbon nanotubes (orother fullerenes) can be employed as the sensing element(s). Further, insome other embodiments, a combination of carbon nanotubes and graphenecan be employed as the sensing element.

In some embodiments, the sensing element(s) of the sensor, e.g., carbonnanotubes and/or graphene, can be functionalized with one or moremolecular species to facilitate the interaction of the sensingelement(s) with one or more chemical species of interest. For example,in some embodiments, the sensing elements can be functionalized with oneor more antibodies that can selectively bind to a chemical species ofinterest so as to facilitate its detection, as discussed in more detailbelow.

In some embodiments, the sensing elements of a sensor according to thepresent teachings can be functionalized with one or more antibodies thatselectively bind to one or more gluten proteins. By way of example, insome embodiments, the sensing elements (e.g., carbon nanotubes and/orgraphene) are functionalized with an antibody that can selectively bindto gliadin. An example of a commercially available antibody that canselectively bind to gliadin is an antibody marketed by Abcam ofCambridge, Mass., U.S.A. under the tradename 14D5. This allowsselectively detecting one or more gluten proteins in a food sampleagainst a background of a variety of other species present in that foodsample, as discussed in more detail below.

For example, as shown schematically in FIG. 21A, in one embodiment, thesensing element of a sensor comprises a graphene layer 2100, which isdisposed on an underlying substrate 2102. The underlying substrate canbe formed of a variety of different materials, such as, silicon,polymeric materials, such as polyurethane, polyethylene terephthalate,or glass, among others. In some embodiments, the graphene layer isdisposed over an underlying silicon oxide (SiO₂) layer, which is in turnformed as a thin layer in a silicon substrate (e.g., a layer having athickness in a range of a 200 nm to about 10 microns).

In some embodiments, graphene can be deposited on an underlying siliconsubstrate by using a variety of techniques known in the art. By way ofexample, chemical vapor deposition (CVD) can be employed to depositgraphene on an underlying copper substrate. The graphene-coated coppersubstrate can then be disposed on a silicon oxide layer of a siliconwafer, and the copper can be removed via chemical etching. In someembodiments, the graphene layer is deposited on the underlying substrateas an atomic monolayer, while in other embodiments the graphene layerincludes multiple atomic layers.

In this embodiment, the graphene layer is functionalized with aplurality of antibody molecules 2104. More specifically, in thisembodiment, a plurality of linker molecules 2016 are attached (e.g., viacovalent bonds) at one end thereof to the graphene layer. The linkermolecules are adapted to couple (e.g., via covalent bonds) at anotherend thereof to the plurality of antibody molecules 2014. In this manner,the graphene layer 2100 can be functionalized with a plurality ofantibody molecules.

In this embodiment, a plurality of such antibody molecules can cover afraction of the surface of the graphene layer. In various embodiments,the faction can be at least about 60%, at least about 70%, at leastabout 80%, or 100% of the surface of the graphene layer. The remainderof the surface of the graphene layer (i.e., the surface areas notfunctionalized with the antibody) can be passivated via a passivationlayer 2108. By way of example, the passivation layer can be formed byusing Tween 20, BLOTTO, and/or gelatin. The passivation layer caninhibit, and preferably prevent, the interaction of an analyte ofinterest in a food sample introduced onto the graphene layer with areasof the graphene layer that are not functionalized with the antibodymolecules. This can in turn lower the noise in the electrical signalsthat will be generated as a result of the interaction of the analyte ofinterest with the antibody molecules.

In addition, in this embodiment, at least a portion of the non-bindingsegments of the antibody molecules can be blocked via a blocking reagent2020, as seen in FIG. 21B. The blocking reagent 2020 may inhibit thechemical species of interest (gliadin in this embodiment) from bindingto those portions and potentially generating false positive signals. Insome cases, the blocking reagent can be the same agent employed topassivate the graphene layer, such as those listed above, while in someother cases they can be different. By way of example, in thisembodiment, Tween 20 is employed to passivate exposed portions of thegraphene layer (i.e., the portions of the graphene layer to whichanti-bodies are not attached) and gelatin (GF) is employed to block thenon-binding segments of the anti-bodies.

By way of example, with reference to FIGS. 22A-22F, in some embodiments,1-pyrenebutonic acid succinimidyl ester, depicted in FIG. 22A, isemployed as a linker to facilitate the coupling of anti-gliadin antibodymolecules 2104 to the underlying graphene (or other fullerenes) layer2100. As noted above, the anti-gliadin antibody can be 14D5 antibodymarketed by Abcam for selectively binding to the gliadin protein. Otherlinkers and/or antibodies can also be used. The selection of the linkerand the antibody depends, at least in part, on the type of applicationfor which the device is employed, the desired bonding level of theantibody to an analyte of interest, the cost of the linker and/or theantibody, etc. The attachment of the linker molecules (1-pyrenebutonicacid succinimidyl ester in this embodiment) is schematically depicted inFIG. 22C.

By way of example, in some embodiments, a graphene layer formed on anunderlying substrate (e.g., plastic, a semiconductor, such as silicon,or a metal substrate, such as a copper film) can be incubated with thelinker molecule (e.g., a 5 mM solution of 1-pyrenebutonic acidsuccinimidyl ester) for a few hours (e.g., 2 hours) at room temperature.

The linker modified graphene layer can then be incubated with anantibody (e.g., 14D5) in a buffer solution (e.g., NaCO₃—NaHCO₃ buffersolution (pH 9)) at a selected temperature and for a selected duration(e.g., 7-10 hours at 4 C), followed by rinsing with deionized (DI) waterand phosphate buffered solution (PBS). In order to quench the unreactedsuccinimidyl ester groups, the modified graphene layer can be incubatedwith ethanolamine (e.g., 0.1 M solution at a pH of 9 for 1 hour). FIG.22D schematically depicts the coupling of the antibody molecules (inthis embodiment anti-gliadin antibody molecules) to the linker moleculespreviously attached to the graphene layer.

Subsequently, the non-functionalized graphene areas can be passivatedvia a passivation layer 2108, as shown schematically in FIG. 22E. Thepassivation of the non-functionalized portions of the graphene layer canbe achieved, e.g., via incubation with 0.1% Tween 20.

While in some embodiment a single type of antibody molecule is employedto functionalize the entire graphene layer, in other embodiments,different types of antibody molecules can be used to functionalize thegraphene layer.

Referring now to FIG. 23, the cartridge 1900 includes a food chamber2300 for receiving a food sample (herein also referred to as the “foodchamber”), which is disposed above the sensor 2000. The food chamber2300 includes an input port 2300 a through which a food sample can beintroduced into the food chamber and an output port 2300 b. In thisembodiment, the food chamber 2300 includes a top portion 2301 and alower portion 2302. The top portion 2301 is slightly slanted relative tothe top surface of the cartridge and exhibits a flared cross-section.The lower portion 2302 is substantially vertical and can function as acapillary tube for transferring a liquid mixture of at least a portionof the food sample and a process liquid into the underlying sensor, asdiscussed in more detail below.

In this embodiment, one or more filters 2303 are disposed between theoutput port of the food chamber and the underlying sensor. In otherembodiments, the cartridge may not include such filters and the liquidmixture, via extraction of a portion of the food sample by a processliquid, can be directed onto the sensor (e.g., onto a functionalizedgraphene layer) without first passing through one or more filters.

The cartridge further includes a liquid reservoir 2304 in which aquantity of a process liquid is stored. A variety of process liquids canbe employed. By way of example, in some embodiments, the process liquidincludes an alcohol (e.g., ethanol). In some embodiments, the processliquid can be a mixture of water and alcohol with the volumeconcentration of alcohol ranging, e.g., from about 10% to about 70%,e.g., in a range of about 15% to about 50%.

In some embodiments, the volume of the liquid reservoir can be in arange of about 0.1 milliliters (ml) to about 0.2 ml, and the volume ofthe chamber for receiving the food sample can be in a range of about0.03 ml to about 0.1 ml, although other volumes can also be employed.

The food chamber 2300 is separated from the liquid reservoir by a thinfrangible membrane 2306. In some embodiments, the thickness of thefrangible membrane can be less than about 5 microns, for example, in arange of about 2 microns about 5 microns.

A variety of different materials can be used to fabricate the cartridgeincluding the frangible membrane. Some examples of such materialsinclude, without limitation, PMMA (polymethymethacrylate), PDMS(polydimethysiloxane). Further, a variety of fabrication techniques,such as molding, can be utilized to fabricate the cartridge.

With continued reference to FIG. 23, in use, a user can peel back thepeelable layer 1901 to expose the input port 2300 a of the food chamber.The user can introduce a food sample into the food chamber and reapplythe peelable cover 1901. The cartridge 1900 can then be placed in theanalyzer. The user can apply a compressive pressure to the liquidreservoir 2304 (as shown schematically by the vertical arrow) to causethe rupture of the frangible membrane 2306, thereby allowing at least aportion of the process liquid stored in the liquid reservoir 2304 toenter the food chamber. In some embodiments, the closing of the cover ofthe analyzer can result in application of the compressive pressure(e.g., via a protrusion provided in the cover adapted to be in registerwith a thin upper wall of the liquid reservoir) on the liquid in thereservoir. The liquid can in turn transfer the applied pressure to thethin frangible membrane, which separates the liquid reservoir from thefood sample chamber.

Once the pressure exceeds a threshold, the membrane ruptures allowingthe process liquid to enter the food chamber. The process liquid canextract, e.g., via solvation, certain constituents of the food samplestored in the food chamber. The resultant mixture can exit the foodchamber via its output port to be introduced onto the underlying sensor,e.g., after passage through one or more filters. In some embodiments,such a mixture can be in the form of a solution or a colloidal mixture.As discussed in more detail below, in some embodiments, the food samplesolution can be drawn via capillary forces to one or more filtersdisposed between the food chamber and the sensor.

In some embodiments, rather than using a thin frangible membrane, othermechanisms can be employed for providing a breakable separation betweenthe food chamber and the liquid reservoir. By way of example, FIGS. 27Aand 27B show a modification of the cartridge 1900 in which aconstriction, rather than a frangible membrane, separates a food chamberfrom a liquid chamber. More specifically, FIGS. 27A and 27B show partialschematic views of a cartridge 2700 according to an embodiment.Cartridge 2700 includes a chamber 2702 for receiving a solid and/orliquid food sample, and an adjacent chamber 2704 for containing aprocess liquid, e.g., an alcohol or an aqueous solution of an alcohol. Anormally constricted channel 2706 separates the food chamber 2702 fromthe liquid chamber 2704, thus preventing the flow of the liquid into thefood chamber. Once a food sample has been introduced into the chamber2702, a user can apply pressure to a surface area above the constrictedchannel (as shown schematically by the vertical arrow) to cause at leastpartial opening thereof, as shown in FIG. 27B, so as to allow at least aportion of the process liquid in the chamber 2704 to be introduced intothe food sample channel 2702. The process liquid can dissolve at least aportion of food sample and the resultant solution can then be introducedvia a capillary tube through one or more filters onto the sensingelement(s) of the cartridge, e.g., in a manner discussed above.

In yet another embodiment, as shown in FIGS. 28A and 28B, a sharp needle2800 can be employed. Sharp needed 2800 can puncture a frangiblemembrane 2802 separating a liquid chamber 2804 of the cartridge from itsfood sample chamber 2806 to initiate analysis of a food samplepreviously introduced into the food chamber. In this embodiment, theneedle 2800 extends at least partially across the process liquid chamber2804 and includes a sharp tip portion 2800 a that can be pushed againstthe frangible membrane separating the liquid chamber from the foodchamber so as to puncture the frangible membrane. Upon the puncture ofthe frangible membrane, the liquid in the liquid chamber can enter viaan opening 2800 b provided in the needle into a central lumen 2800 c ofthe needle and exit through an output opening provide at the tip of theneedle to enter the food chamber.

With reference to FIG. 28C, in some embodiments, a cap 2810 attached tothe needle 2800 is externally accessible. The cap 2810 enables a user topush the needle toward the frangible membrane separating the liquidchamber from the food chamber. More specifically, the cap includes alow-profile collar 2812 that sits against an external wall of thecartridge when the needle is in a deactivated state. The low-profilecollar 2812 prevents the axial motion of the needle unless activated bya user as discussed below. As the user presses the cap, the collar 2812can flex and pass through the opening 2814 provided in the cartridge'swall. Pressing the cap can then push the tip of the needle into thefrangible membrane separating the process liquid chamber from the foodchamber. The passage of the collar through the opening 2814 can generatea clicking sound that can alert the user that the device has beenactivated.

In some embodiments, a visual and/or audible signal can be employed toinform a user that the cartridge has been activated, i.e., theseparation between the liquid reservoir and the food chamber has beenbroken. For example, the puncture of the frangible membrane can initiatethe generation of an electrical signal that can in turn cause theillumination of a light source, such as an LED, and/or generation of anaudible tone. By way of example, as shown schematically in FIG. 29, twoelectrodes 2901 and 2902 can be placed in a capillary tube 2904 throughwhich a liquid mixture of a food sample and a process liquid passes toreach an underlying sensor. The electrode 2901 is electrically coupledvia a resistor 2905 and a voltage source 2906, e.g., a battery, to alight source 2908. By way of example, the voltage source and/or thelight source can be incorporated in an analyzer to which the cartridge2501 can be coupled. The other electrode 2902 is coupled to the otherside of the light source 2908. Before activation of the cartridge, theelectrodes are separated by the space within the capillary tube, thusresulting in an open circuit. Once the cartridge is activated, asolution of a food sample will pass through the capillary tube, whichcan provide an electrical path between the two electrodes, therebyclosing the circuit comprising the light source so as to activate thelight source.

Referring now to FIG. 30, after introduction of the process liquid(e.g., a solution of alcohol and water) into the food chamber, at leasta portion of a mixture (e.g., a solution) of the food sample and theprocess liquid exits the food chamber via the output port 2300 b, e.g.,via capillary action of the lower vertical portion of the food chamber.The mixture that exits is introduced onto two filters 3000 a and 3000 bthat are disposed below the output port of the food chamber and abovethe sensing element(s) 2002 of the sensor 2000 (e.g.,antibody-functionalized graphene layer in this embodiment).

The filters 3000 a and 3000 b are capable of blocking certain chemicalspecies in a sample under study from reaching the sensing element(s)while allowing one or more other chemical species to pass through toreach those elements. A double sided tape 3002 having a central openingcan facilitate fixating the filters 3000 a and 3000 b while allowing theliquid exiting the food chamber to reach the sensing element(s) 2002 viaits central opening.

In some embodiments, one of the filters (e.g., 3000 a) can be anoleophobic filter that can block oily substances (e.g., substancesincluding fat molecules) from reaching the sensing elements. By way ofexample, the oleophobic filter can be obtained from Donaldson FiltrationSolutions of Minneapolis, U.S.A. under tradename Dura-life oleophobicfilter or can be obtained from Gore of Newark Del. The other filter(e.g., filter 3000 b) can be hydrophobic so as to inhibit chemicalspecies that are soluble in water from reaching the sensing element(s)2002. By way of example, the hydrophilic filter can be a Teflon® coatedfilter.

In some embodiments, rather than employing two filters as discussedabove, a single filter can be used that exhibits both hydrophobic andoleophobic properties. In some embodiments, such a filter canselectively allow the passage of chemical species soluble in an alcoholthrough the filter. An example of a suitable filter is disclosed in thesection below, which discusses an oleophobic hydrophobic filter.

Briefly, such a filter includes a substrate having a top surface towhich a polymeric material is applied. Such a polymeric material can be,for example, a polymer known as Nafion®, which is marketed by DupontChemical Company of Wilmington Del., U.S.A. A variety of substrates canbe employed. In some embodiments, the substrate is porous and includescellulose fibers. As discussed in more detail below, in someembodiments, such a filter can be employed in a device according to thepresent teachings for detecting gluten proteins in a sample.

Other filters can also be employed to practice the present teachings. Byway of example, U.S. Pat. No. 8,695,810 entitled “Superoleophobic andsuperhydrophilic Fabric Filters for Rapid Water-Oil Separation,” whichis herein incorporated by reference in its entirety, discloses a filterthat can be employed in some embodiments of the present teachings.

The portion of the solution that has passed through the filters 3000 aand 3000 b (herein also referred to as the filtrate) reaches the sensingelement(s) of the underlying sensor. As discussed above and shownschematically in FIG. 21A, in this embodiment, the sensing element is agraphene layer that has been functionalized by a plurality of antibodymolecules. By way of example, the graphene layer can be functionalizedwith antibody molecules that selectively bind to the gliadin protein. Ifgluten is present in the filtrate reaching the sensing element, thebinding of the gliadin molecules to the antibody molecules can cause ina change in one or more electrical properties of the underlying graphenelayer.

By way of example, the binding of the gliadin molecules to the antibodycan modulate the electrical resistance of the underlying graphene layer.The modulation of the electrical resistance of the graphene layer can bedetected and analyzed to determine whether gliadin protein is present inthe food sample. It should be understood that the teachings of thepresent disclosure are not limited to detecting gluten proteins in afood sample, but can be employed to detect other chemical species,including a variety of proteins and other analytes in a food sample.

Referring again to FIG. 16A, the analyzer 1606 can be implemented in amanner discussed above in connection with analyzer 12 to receiveelectrical signal(s) associated with the sensing element(s) of thesensor and analyze those signals to determine, e.g., the probabilitythat a species of interest (such as gluten) is present in a food sample,and optionally quantify the concentration of that species.

More specifically, FIG. 31 schematically shows an analyzer 1606according to some embodiments. The analyzer 1606 can include a dataacquisition module 3100 and a data analysis module 3102. The dataacquisition module 3100 can detect electrical signal(s) generated by thesensing elements of the sensor in response to interaction with a foodsample. The data analysis module 3102 can analyze the detected signalsto determine whether at least one species of interest, such as gluten,in present in the food sample.

With reference to FIGS. 31A and 33A, in this embodiment, the dataacquisition module 3100 can include a circuit 701 for measuring changesin the electrical resistance of the sensing elements of the sensor 1614.The changes may be caused by the interaction of the sensing element(s)of the sensor with one or more species present in a food sample understudy. In some embodiments, the sensing elements can exhibit anelectrical resistance, for example, in a range of about 300 kΩ to about10 MΩ The electrical resistance can change in response to interaction ofthe sensing elements with one or more analytes in a sample to which thesensing elements are exposed. Such a change in the electricalresistance, and in some cases the change in the electrical resistance asa function of time, can provide a signature of the analyte of interest.

More specifically, FIG. 33A shows an exemplary circuit 701 that can beemployed for measuring electrical resistance of a sensor, e.g., sensor702 that is depicted in this figure as an equivalent circuit diagram ofa sensor according to the present teachings. A fixed voltage V (e.g.,1.2 V) is generated at the output of a buffer operational amplifier 703.This voltage is applied to one input (A) of a downstream operationalamplifier 704 having another input B that is coupled to a variablevoltage generator operational amplifier 705 via a variable resistor R1.The output of the operational amplifier 704 (Vout 1) is coupled to oneend of the sensor 702 and the input B of operational amplifier 704 iscoupled to the other end of the sensor 702. In this schematic diagram,resistor R2 denotes the resistance between two electrode pads at one endof a sensor, resistor R3 denotes the resistance of the nanotubes (orgraphene or other fullerenes) of a sensor extending between twoelectrode pads of the sensor, and resistor R4 denotes the resistancebetween two electrode pads at the other end of the sensor. Theoperational amplifier 704 maintains the voltage at the input B at thefixed voltage applied to its input (A), e.g., 1.2 V. An adjustablecurrent source is generated by operational amplifier 705 and adjustableresistor sR1 and R6, which push an adjustable current flow through thesensor 702. The voltage V1 and V2 generated across the resistor R3 areapplied, respectively, to an input of each of the operational amplifiers706 and 708. As the other input of each of the operational amplifiers706 and 708 is coupled to their respective outputs, the voltage V1 andV2 appear at the outputs of the operational amplifiers 706 and 708. Thevoltages V1 and V2 are then applied to the two inputs of a differentialoperational amplifier 710 whose output is indicative of a differencebetween V1 and V2 (designated as Vout1_GLO). The voltage difference(V1−V2) together with the known current applied to R3 can then be usedto determine the resistance of R3 (i.e., the resistance of one or moresensing elements). As discussed above, the measurement of the resistanceas a function of time, in response to exposure of the sensing element toan liquid under test, can then be analyzed to determine the presence (orthe probability of presence) of an analyte of interest in that liquid.The value of Vout1_GLO is equal to V1−V2+Vdc. Vdc is another referencevoltage generated by the circuit.

FIG. 33B shows a variation of the above circuit depicted in FIG. 33Aaccording to an embodiment. In FIG. 33B, an NMOS, n-channel metal oxidesemiconductor, transistor is added to the output and the minus input ofthe amplifier 7041. The voltage at the drain of the NMOS resistorprovides the voltage Vout2 that is applied to one end of the resistorchain R2-R3-R4. Another voltage Vref provides, via operational amplifier8001, the voltage Vout1 that is applied to the other end of the resistorchain R2-R3-R4.

In this circuit the adjustable current source generated by operationalamplifier 705 and adjustable resistors R1 and R6 push the adjustablecurrent flow through the NMOS transistor which is then forced into thesensor 7021.

The voltage difference (Vout1−Vout2) generates a current through theresistor R3 whose resistance is to be measured. The use of the NMOStransistor eliminates the connection of the minus input of theoperational amplifier 7041 to the resistor R3, thereby eliminating thepotential of oscillations that such connection might cause.

Referring back to FIG. 31B, the data analysis module 3102 receives themeasured electrical data from the data acquisition module 3100 andoperates on that data, e.g., in a manner discussed below. The operationdetermines whether a species of interest, e.g., gliadin, is present in afood sample. Such determination can be in the form of determining theprobability that a species of interest is present in the sample. In someembodiments, if the concentration of the species of interest is lessthan the detection sensitivity of the device, the analysis module mayindicate that the species is not present in the food sample.

In some embodiments, the data analysis module 3102 compares the temporalvariation of an electrical signal generated by the sensing elements witha calibrated temporal profile of one or more species of interest todetermine the probability of presence of those species in a sample understudy. By way of example, in some embodiments, the probability that afood sample contains gluten proteins can be ascertained in the followingmanner.

In some embodiments, a visual inspection of a measured temporalvariation and its comparison with a calibrated temporal profile can beemployed to determine whether an analyte of interest is present in afood sample (or a measure of the probability that the analyte is presentin the food sample). In other embodiments, an algorithm, such a curvematching algorithm, can be employed to compare a measured temporalprofile with a calibration profile, as discussed in more detail below.

A food sample is brought into contact with an aqueous solution ofethanol, e.g., in a manner discussed above. A mixture of at least aportion of the food sample and the aqueous solution is passed throughone or more filters and brought into contact with a graphene layerfunctionalized with anti-gliadin antibody molecules, in a mannerdiscussed above. An electrical signal associated with the sensingelements in response to interaction of the mixture with theantibody-functionalized graphene layer (e.g., variation of voltage orcurrent generated by the sensing elements) is collected via the dataacquisition module 3100 over a period of time.

The data analysis module 3102 receives the electrical signal from thedata acquisition module. The data analysis module 3102 may compare thetemporal variation of the electrical signal with a previously-obtainedcalibration signal to determine how closely the measured electricalsignal resembles the calibration signal. For example, a merit functioncan be employed for comparison of the measured electrical signal withthe calibration signal to determine the probability that a species ofinterest is present in a sample. In some cases, pattern recognitiontechniques can be employed to assess whether the obtained signal matchesa calibration signals.

Various embodiments may employ a curve matching technique. One exampleof such a technique is discussed in an article entitled “Curve Matching,Time Warping, and Light Fields: New Algorithms for Computing SimilarityBetween Curves.” The techniques are employed to compare a temporalsignal obtained in response to the interaction of the sensing elementswith a food sample with at least one calibration signal associated witha species of interest. The comparison may assess how well a curverepresenting the temporal variation of the signal matches thecalibration curve in order to estimate the probability that the speciesis present in the sample.

By way of example, when the chemical species of interest is one or moregluten proteins, one or more calibration samples containing knownamounts of one or more gluten proteins can be employed. The electricalsignals associated with the sensing elements of the sensor in responseto interaction (e.g., contact) with one or more calibration samples canbe measured to generate calibration signals. In some cases, measurementsof multiple calibration samples can be performed and averaged togenerate an average calibration signal (curve). The probability that oneor more gluten proteins are present in a food sample can then bedetermined by comparing a curve representing temporal variation of anelectrical signal generated by the sensing elements in response tointeraction with the food sample with the calibration curve(s).

In embodiments in which one or more filters and antibody functionalizedgraphene are employed, the presence of an analyte of interest can bedetermined by detecting a statistically significant variation of theelectrical signal in response to interaction of the functionalizedgraphene with the sample.

Returning to FIGS. 31A and 31B, the data analysis module 3102 can beimplemented in hardware, software, firmware or a combination thereof. Byway of example, as depicted in FIG. 31B, the data analysis module 3102can include a processor 3200, permanent memory 3202, random accessmemory (RAM) 3204, a communication bus 3206, and a communication module3208. The communication bus 3206 may connect the processor with thememory 3202 and 3204. The communication module 3208 may communicate withthe data acquisition module 3100, among other components known in theart. Instructions for operating on the received data in a mannerdiscussed above, as well as calibration data, can be stored in thepermanent memory 3202. Upon receipt of electrical data from the dataacquisition module, such data can be stored in the RAM 3204 undercontrol of the processor 3200. The process can then effect the transferof the data analysis instructions (or at least the needed portionsthereof) and the calibration data into the RAM 3204. The processor willutilize the instructions and the calibration data to operate on thereceived data so as to determine whether the species of interest in thepresent in the food sample in a manner discussed above.

In some embodiments, the result of the analysis performed by the dataanalysis module 3102 can be transferred to a mobile device forpresentation to a user via a graphical user interface (GUI) of themobile device. For example, the results can be transferred via awireless protocol (e.g., Bluetooth or WiFi protocols) to a user's mobiledevice (e.g., mobile phone, tablet, etc.) to be presented to the user.By way of example, a client program residing on the mobile device cancommunicate with data analysis module 3102 to receive the analysisresult. The client program can be, for example, a downloadable appoperating under off-the-shelf standard mobile operating systems (e.g.,IOS, Android, Microsoft, etc.).

Referring again to FIG. 31B, the data analysis module 3102 can furtherinclude a network communication interface (e.g., a wirelesscommunication interface) 3208 to allow the analysis module tocommunicate with other network-enabled devices to transfer the resultsof the analysis of the data to those devices. By way of example, asnoted above, the data analysis module 3102 can communicate via awireless protocol to other devices. In some embodiments, the dataanalysis module 3102 can communicate via the Bluetooth protocol to sendthe results of analysis of a sample under study to a user's device,e.g., a mobile device such as a mobile phone or a tablet, forpresentation to the user.

Some embodiments employ a software application (herein also referred toas an app) for presenting the analysis results to a user. The softwareapplication can be configured to be executable on a mobile device, suchas a mobile phone, and can receive the analysis data from the dataanalysis module 3102 and present that data to a user. By way of example,FIG. 31C shows the graphical user interface (GUI) 3200 of such an app.GUI 3200 can present the result of analysis of a food sample todetermine the probability of presence of gluten proteins in that sample.A graphical element 3201 graphically depicts the probability that one ormore gluten proteins are present in a food sample. The GUI 3200 allows auser to scan for the analyzer and connect, e.g., via Bluetooth, to theanalyzer. The GUI 3200 further allows a user to instruct the analyzer tocalculate the probability that gluten is presence in the sample.

B. FOOD GRINDING MECHANISMS

Some embodiments use food grinding mechanisms to grind or press a foodsample before exposing it to a process liquid. Doing so may increase thesurface area of the food sample and cause it to better mix and interactwith the process liquid. Different embodiments may use different foodgrinding mechanisms. Some of these mechanisms are discussed below.

Referring now to FIGS. 24A-24D, in some embodiments, a device isemployed to grind and/or crush a food sample prior to introducing itinto the food chamber of a cartridge according to the present teachings.Such a device can be a stand-alone device or can be integrated with thecartridge, as discussed below. By way of example, FIGS. 24A-24D depictsuch a device 2400 for grinding a food sample. The device 2400 includesa base 2402 that includes a helical structure 2404. Helical structure2404 provides an internal serpentine path 2404 a. The internal pathterminates in a well 2406 in which the ground food sample can becollected, as discussed below. The device 2400 further includes a cover2408 that is hingedly attached to the base 2402. A rotatable pinion 2410is disposed in the cover, which is coupled to a rack 2412. The pinion2410 includes a groove 2410 a in which a grinding element 2414 isengaged. The grinding element 2414 is configured such that upon closureof the cover it engages at an end thereof within the internal serpentinepath provided by the helical structure. A knob 2416 is attached to therack to allow linearly moving the rack and hence rotating the pinion.

In use, a user opens the cover 2408 and places a food sample within theserpentine path and closes the cover. The user then uses the knob 2416to rotate the pinion 2410. The rotation of the pinion in turn causes thegrinding element to move along the serpentine internal path provided bythe helical element and hence grind the food sample and push the groundfood sample into the well 2406. The user can open the cover and collectthe crushed food sample and introduce it into the food chamber of thecartridge 1900.

Alternatively, in some embodiments, the food grinding device isintegrated with the cartridge 1900. In such embodiments, the well 2406of the grinding device can be modified to be an opening in register withthe input port of the food chamber of the cartridge. In such cases, theground food sample may be introduced into the food chamber at the distalend of the serpentine path provided by the helical element.

Other devices for grinding the food sample can also be employed. FIG. 25schematically shows another grinding mechanism according to someembodiments. In particular, FIG. 25 schematically depicts that in someembodiments, the protective cover 1901 of the cartridge can include aprotrusion 2500 having an abrasive, corrugated surface 2500 a forgrinding a food sample introduced in the food chamber 2300 of thecartridge. Specifically, the user can partially peel off the cover 1901to expose the cartridge's food chamber. A food sample can then beintroduced into the food chamber. Upon reapplication of the protectivecover 1901, the abrasive surface 2500 a of the protrusion 2500 willcompress and grind the food sample.

FIG. 26 schematically shows yet another grinding mechanism according tosome embodiments. In FIG. 26, a food crushing device 2600 includes abarrel 2602 and a plunger 2604 that is movable within the barrel. Inthis embodiment, the outer surface of the plunger is an abrasive surfaceso as to crush a food sample drawn into the barrel as the plungeradvances in the barrel.

In some embodiments, a cartridge according to the present teachings cancomprise a plurality of sensors. By way of example, FIGS. 32A and 32Bschematically depict a cartridge 3200 in accordance with someembodiments in which two sensors 3202, 3204 are incorporated. Each ofthe sensors can be constructed in a manner discussed above. For example,as shown schematically in FIG. 32B, sensors 3202 and 3204 include,respectively, sensing elements 3202 a and 3204 a. These sensing elementsmay include as a plurality of carbon nanotubes, graphene and/or otherfullerenes. A plurality of metallic pads 3202 b and 3204 b areelectrically coupled to the sensing element 3202 a/3204 a, respectively,to allow reading variation of at least one electrical property of thesensing element(s), e.g., electrical resistance, in response tointeraction with one or more species in a food sample.

Without any loss of generality, in the present embodiment, one of thesensors (e.g., sensor 3202) includes a graphene layer that isfunctionalized with an anti-gliadin antibody in a manner discussedabove. The other sensor (e.g., sensor 3204) also includes a graphenelayer. But the graphene layer of the sensor 3204 may be functionalizedwith an isotype of the anti-gliadin antibody employed to functionalizethe sensor 3202. The isotype antibody is similar to the anti-gliadinantibody except that it does not selectively bind to gliadin. In someembodiments, the graphene layer of one sensor can be functionalized withone gluten protein and the graphene layer of the other sensor can befunctionalized with another gluten protein.

The sensors 3202/3204 are configured such that they can concurrently, orsequentially, receive different portions of a sample under study todetermine the presence (or the probability of the presence) of one ormore species of interest in the sample. In this embodiment, the signalgenerated by the sensor 3204 in response to interaction with a foodsample is employed as a calibration signal against which the signalgenerated by the sensor 3202 is evaluated.

C. OLEOPHOBIC HYDROPHOBIC FILTERS

Some embodiments use oleophobic filters. In some embodiments, anoleophobic filter can be concurrently hydrophilic or hydrophobic.

There is a need in a variety of applications for separating constituentsof a sample. In particular, there is a need for enhanced filters andseparation methods.

In one aspect, a filter is disclosed, which comprises a substrate, and apolymeric material applied to a top surface of the substrate, where saidpolymeric material comprises a polymer having the following chemicalstructure:

A variety of different substrates can be employed. For example, in someembodiments the substrate can be hydrophilic while in other embodimentsthe substrate can be hydrophobic. By way of example, in someembodiments, the substrate can comprise cellulose fibers.

In some embodiments, the filter can be concurrently oleophobic andhydrophilic. In some other embodiments, the filter can be concurrentlyoleophobic and hydrophobic. In some embodiments, the filter can beoleophobic but allow the passage of alcoholic solutions.

FIGS. 34A and 34B schematically depict a filter according to anembodiment of the present teachings, which includes a cellulose-basedsubstrate 3400 having a top surface 3400 a that is treated with apolymeric material 3402. The substrate 3400 can be formed of a varietyof different materials, which can exhibit hydrophobicity orhydrophilicity. In some other embodiments, the substrate may be formedof polytetrtaethylene (e.g., Teflon®).

In some embodiments, the substrate 10 is a porous substrate. By way ofexample, the substrate 10 can have pores with sizes in a range of about1 micrometer to about 100 micrometers.

In some embodiments, the polymeric material 3402 is dispersed over thetop surface 3400 a. While in some embodiments, the polymeric material3402 can substantially cover the entire surface 3400 a of the substrate3400, in other embodiments, it can cover only portions of the surface3400 a. Without loss of generality, in the following discussion, thesubstrate 3400 is assumed to have a porous cellulose structure.

In this embodiment, the polymeric material is sulfonatedtetrafluoroethylene based fluoropolymer-copolymer. For example, thepolymeric material can be ethanesulfonyl fluoride,2-[1-[difluoro-[(trifluoroethenyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2,-tetrafluoro,copolymer with tetrafluoroethylene. In some embodiments, the polymericmaterial can betetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acidcopolymer.

An example of such a polymeric material is a polymer commonly known atNafion®, which is marketed by Dupont Chemicals Company of WilmingtonDel., U.S.A. Nafion® is a synthetic polymer with long strands of CF₂moiety as its backbone and branches of H—SO₃, known as sulfonate, whichcan be a source of protons. Nafion® has the following molecularstructure:

Without being limited to any particular theory, the Nafion® backbone ishydrophic, but under certain conditions the sulfonic functional groupscan self-organize so as to create a plurality of channels through whichwater molecules can be transported.

As discussed further below, a filter according to the present teachingscan be oleophobic, i.e., it can impede and preferably prevent thepassage of fatty molecules through the filter. Without being limited toany particular theory, the CF groups of Nafion impart such oleophobiccharacter to the filter. In addition, the cellulose substrate can behydrophobic. Hence, the combination of Nafion and the cellulosesubstrate can provide a filter that is concurrently oleophobic andhydrophic.

In some embodiments, the filter can impede the passage of fattymolecules but allow the passage of alcohol (e.g., methanol or ethanol),or an aqueous solution of alcohol through the filter.

A filter according to the present teachings can be used in a variety ofdifferent applications. For example, as discussed above, the filter canbe employed in a cartridge according to the present teachings fordetecting the presence of an analyte, e.g., a gluten protein, in a foodsample.

In some exemplary embodiments, Cellulose filter papers with a porosityof 200 1.n were obtained from Sigma Aldrich (GE filter 42). Each filterpaper was used as a supporting substrate onto a surface of which Nafion®was applied.

In order to obtain a substantially uniform distribution of the Nafionparticles on the cellulose filter surface, ink spraying method was usedfor applying the Nafion dispersion onto the cellulose filter surface.More specifically, the cellulose filter paper was placed in a tubularstructure with a substantially uniform diameter of D (approximately 2-3inches) and a length of equal to or greater than 10D. An exhaust fan wasplaced downstream of the tubular structure so as to generate a negativepressure in the upstream of the flow.

More specifically, the filter paper was introduced into a conduitprovided by the tubular structure and was secured in its place at alength of about 2D from downstream end side of the conduit. To preventthe filter paper from bulging and possibly rupturing the surface of theholder, a fine metallic mesh was placed around the holder to secure thefilter. At a distance of D from the inlet of the conduit, a sprayingnuzzle was disposed to ensure uniform application of the Nafionparticles onto the filter surface. The spray nozzle was then used tocoat the exposed surface of the filter paper with the aforementionedNafion® dispersion.

The coated filter was kept in an oven maintained at a temperature of 86°C. for 1 hour so as to form more stable bonds between Nafion® andcellulose structures.

FIG. 35A shows an image of untreated and Nafion-treated GE filters whenexposed to cooking oil. FIG. 35B shows images of untreated andNafion-treated GE filters when exposed to ethanol. FIG. 35C shows imagesof untreated and Nafion-treated GE filters when exposed to deionized(DI) water. The images show that the Nafion-treated filters preventpassage water as well as oily substances while allowing ethanol to passthrough.

D. PROCESSING AND DETECTION SYSTEMS

Some embodiments employ a processing and detection system to detectpresence of a molecule, such as a gluten protein, in a food sample. Insome embodiments, the processing and detection system includes a foodprocessor and a detector. In some embodiments, the food processor isconfigured to receive a food sample and process it by mixing it with aprocess liquid and extracting a processed food liquid, which can beanalyzed by the detector. In some embodiments, the detector includes acartridge, which can analyze the processed food liquid and detectpresence of the molecule in the processed food liquid.

FIGS. 36A-36D schematically depict a food processor 3600 according to anembodiment. The food processor 3600 includes a tubular body 3602, aplunger 3606, a liquid reservoir 3614, and a strainer plate 3616.

As further detailed below, the tubular body 3602 is configured toreceive a solid food sample. The plunger 3606 is configured to push andcrush the received food sample inside the tubular body 3602. The liquidreservoir 3614 contains a process liquid for processing the crushed foodsample. The strainer plate 3616 is configured to hold the liquidreservoir 3614 at a distal end of the tubular body 3602, and enables theplunger to puncture and squeeze the liquid reservoir and cause thecrushed food sample to mix with the process liquid.

One or more of the tubular body 3602, the plunger 3606, and the strainerplate 3616 can be manufactured using methods such as injection moldingmethod using polyurethane plastics.

The tubular body 3602 is in the form of a hollow cylinder having aproximal end 3602 a and a distal end 3602 b. The tubular body 3602 hasan opening 3604 at the proximal end 3602 a for receiving the plunger3606. Moreover, the peripheral cylinder of the tubular body 3602 forms asample opening 3603 for receiving the sold food sample.

The plunger 3606 extends from a proximal end 3606 a to a distal end 3606b. At the proximal end 3606 a, a disk 3608 is attached to the plunger3606. The disk 3608 allows a user to push the plunger into, or retractthe plunger from, the hollow tube 3602. The distal end 3606 b of theplunger forms a pressing surface that is configured to press on the foodsample or on liquid reservoir 3614, as detailed below. The pressingsurface contains a plurality of pins 3610 disposed on the plunger 3606for facilitating the crushing of the food sample, as discussed below inmore detail.

In some embodiments, the pins 3610 can have conical, pyramidal, or othershapes that provide a sharp tip for facilitating the crushing of thesolid food sample introduced into the tubular body 3602. A pin may havea cylindrical body (A) and a conical tip (B). The pins can be formed ofany suitable material. By way of example, in some embodiments, the pinscan be formed of a metal, such as stainless steel. In other embodiments,the pins can be formed of other materials, such as plastic.

Referring again to FIGS. 36A-36D, the plunger 3606 can be pulled backbeyond the opening 3603 to allow the introduction of the food sampleinto the interior of the cylinder of the tubular body 3602 via theopening 3603.

The liquid reservoir 3614 contains a process liquid 3615 and is disposedin the hollow tubular body 3602 close to its proximal end 3602 b. Asshown in FIG. 36D, in this embodiment, the liquid reservoir 3614 is inthe form of a bag that is placed within the hollow cylinder of thetubular body 3602. The liquid reservoir 3614 can be maintained withinthe tubular body 3602, e.g., via a friction fit or other knownmechanisms. In this embodiment, the liquid reservoir 3614 is formed of asoft polymeric material. Some examples of suitable polymeric materialsinclude, without limitation, polyurethane, low density polyethylene(LDPE), polyvinyl chloride, polyisobutane (PIB), and poly(ethylene-vinylacetate). The wall of the liquid reservoir 3614 may besufficiently thin so that it can be punctured by the pins 3610 as theuser pushes the plunger into the hollow cylinder and presses the pinsagainst the bag. By way of example, the thickness of the bag's wall canbe in a range of about 0.0002 inches to about 0.001 inches, e.g., about0.0005 inches.

The strainer plate 3616 is disposed between the liquid reservoir 3614and the distal end 3602 b of the tubular cylinder. Moreover, thestrainer plate 3616 is disposed such that a cavity 3620 remains betweenthe strainer plate and the distal end 3602 b. The strainer plate 3616forms a plurality of through openings or holes 3618, each of which isconfigured to receive one of the pins 3610. When the plunger 3606 ispushed through the hollow cylinder, the pins 3610 may pierce the bag andreach the openings 3618. Further, the pins 3610 may proceed through theopenings 3618, thus allowing the distal end 3606 b of the plunger tosqueeze the liquid out of the liquid reservoir 3614.

In various embodiments, the strainer plate 3616 may be formed as aseparate unit and then fitted in the tubular body 3602, or it may bemade as an integral unit with the rest of the tubular body 3602.

The cavity 3620 separates the strainer plate 3616 from a nozzle 3622disposed at the distal end 3602 b of the hollow cylinder 3602. Asdiscussed in more detail below, the use of the food processor results inthe accumulation of at least a portion of the process liquid in thecavity 3620, which can be subsequently injected into a cartridge.

More specifically, when using the food processor 3600, a user mayinitially pull back the plunger 3606 such that the plunger 3606 ispositioned between opening 3603 and proximal end 3602 a. The user canthen introduce a food sample into the tubular body 3602 via the opening3603, and push the plunger 3606 toward the bag 3614. After the distalend 3606 b of the plunger reaches the bag 3614, the user may continue topress the plunger towards the distal end 3602 b and against the bag3614. This pressing may cause the pins 3610 to pierce the bag to releasethe process liquid contained in the bag. The process liquid interactswith the food sample to extract an analyte of interest that may bepresent in the food sample. For example, when the analyte of interest isgliadin, the process liquid can be a mixture of alcohol and water. Asdiscussed above, such a mixture can dissolve gliadin therein.

In some embodiments, when the food sample is a solid, the pressing ofthe plunger against the bag 3614 may also cause crushing of the foodsample by the distal end 3605 b, including pins 3610. The food samplecan be crushed as the pins 3610 press against the liquid bag 3614,pierce the bag, or engage with the openings 3618. The crushing of thefood sample can provide more surface area for the interaction of theprocess liquid with the food sample, thereby facilitating the extractionof the analyte of interest from the food sample. More specifically, asthe pins enter the openings 3618 of the strainer plate 3616 the foodsample is further crushed mixed with the process liquid. The liquid partof the resulting mixture, here called the processed food liquid, whichmay contain the analyte of interest via interaction with the foodsample, can enter the cavity 3620.

FIG. 37 schematically depicts a food processor 3700 according to anotherembodiment. The food processor 3700 includes a body 3710, an arm 3720,and a liquid reservoir 3730. Different parts of food processor 3700 maybe made of a variety of different materials and using differentmanufacturing methods. By way of example, each of body 3710 and arm 3720may be formed of a plastic using injection molding or other suitabletechniques.

Liquid reservoir 3730 may contain a process liquid for processing thefood sample. Liquid reservoir 3730 may be in the form of a bagfabricated of a soft polymeric material such as polyurethane or othersuitable polymeric materials. The bag's wall can be sufficiently thin,e.g., it can have a thickness in a range of about 0.0005 inches Moregenerally, the bag's wall may have a thickness or a weakened section,which allows a user to use a pressing or puncturing mechanism, asdetailed below, to puncture the bag by exerting a moderate pressure onthe bag. The pressure may be in a range of about 1 psi to about 3 psi.While in general a plurality of different process liquids can be storedin reservoir 3730, in some embodiments the process liquid can be alcoholor an aqueous solution of alcohol. As discussed earlier, when a foodprocessor is employed together with a cartridge for detecting gluten ina food sample, the alcohol can dissolve one or more gluten proteins, ifany, in the food sample under study. In some embodiments, reservoir 3730can have a liquid volume in a range of, e.g., from about 0.5 ml to about1 ml.

Body 3710 includes a hinge 3712, a reservoir enclosure 3714, a liquidchannel 3715, a food chamber 3716, a processed liquid channel 3717, andan exit port 3718. Hinge 3712 is configured to provide a hinge betweenbody 3710 and arm 3720. Reservoir enclosure 3714 is configured to houseliquid reservoir 3730. Liquid channel 3715 connects reservoir enclosure3714 to food chamber 3716. Liquid channel 3715 is configured to providea conduit for the process liquid to flow from reservoir enclosure 3714to food chamber 3716. Food chamber 3716 is configured to contain a foodsample that can be, for example, solid, liquid, or a sold-liquidmixture. Processed liquid channel 3717 connects food chamber 3716 toexit port 3718. Processed liquid channel is configured to provide aconduit for a processed food liquid to flow to exit port 3718 after itis generated in food chamber 3716. Exit port 3718 provides a conduit forthe processed food liquid to exit body 3710 and, for example, enter acartridge, as further detailed below.

In food processor 3700, body 3710 and arm 3720 are elongated. Further,hinge 3712 hingedly attaches body 3712 to arm 3720. In differentconfigurations, arm 3720 rotates about hinge 3712, such that theelongation axes of the two form different angles, shows as angle 3702.For example, to close food processor 3700, arm 3720 is lowered to reston body 3710, such that angle 3702 is approximately zero. FIGS. 37B and37C show two views of a closed food processor 3700 according to anembodiment.

To open food processor 3700, on the other hand, arm 3720 is rotated awayfrom body 3710 to form a non-zero angle 3702, such as the one shown inFIG. 37. In the open configuration, food chamber 3716 may receive thefood sample.

Arm 3720 includes a protrusion 3722 and a food grinder 3724. Protrusion3722 and food grinder 3724 are positioned along arm 3720 such that whenthe food processor is closed, protrusion 3722 enters reservoir enclosure3714, and grinder 3724 enters food chamber 3716.

Reservoir enclosure 3714 may have a shape and dimensions that snug fitsliquid reservoir 3730. In food processor 3700, for example, both liquidreservoir 3730 and reservoir 3714 have cuboid shapes, with the latterhaving slightly larger dimensions. Moreover, protrusion 3722 may have asimilar shape, such that, when the food processor is closed, protrusion3722 presses down upon liquid reservoir 3730 and forces it to rupture.In particular, protrusion 3722 may include a pressure surface 3723,which contacts and presses on liquid reservoir 3730 during the closing.In the embodiment shown in FIG. 37, pressure surface 3723 is the lowersurface of the cuboid that forms protrusion 3722. In some embodiments,pressure surface 3723 may have other shapes or include other parts, suchas sharp pins, to facilitate the rupturing of liquid reservoir 3730.

Also, grinder 3724 may have a shape that partially or fully fills thevolume inside food chamber 3716 when the food processor is closed.Closing food processor 3700 thus causes grinder 3724 to press or grind asolid sample food that may be in food chamber 3716. Moreover, thispressing may facilitate mixing of the sample food and any process liquidthat may be in food chamber 3716. In food processor 3700, for example,food chamber 3716 is shaped as a hollowed sphere portion. Food grinder3724, on the other hand, is also shaped as an inverted solid sphereportion, such that it substantially fits inside food chamber 3716 whenfood processor 3700 is closed. Other embodiments may employ other shapesfor reservoir enclosure 3714, food chamber 3716, protrusion 3722, andfood grinder 3724.

In some embodiments, a user may use a food processor such as foodprocessor 3700 by performing two stages, a placement stage, and agrinding and mixing stage.

In the placing stage, the user may open food processor 3700 by rotatingaim 3720 around hinge 3712 such that angle 3702 increases. After that,the user may place a food sample, e.g., a solid food sample, inside foodchamber 3716. In various embodiments, liquid reservoir 3730 may alreadybe placed inside reservoir enclosure 3714 or may be placed there by theuser during the placing stage.

After the placing stage, the user may perform the grinding and mixingstage. In this stage, the user closes the food processor by rotating arm3720 about the hinge 3712 to decrease angle 3702. During this closing,pressure surface 3723 may come into contact with the surface of liquidreservoir 3730. The user may further press arm 3720 in a direction ofreducing angle 3702 and thus pressing pressure surface 3723 on liquidreservoir 3730. This pressure may rupture liquid reservoir 3730 andrelease the process liquid to flow to food chamber 3716 through liquidchannel 3715.

Moreover, the pressure of arm 3730 may also cause food grinder 3724 topress down on the food sample in food chamber 3716. If the food sampleis solid, this pressure may grind or press it. This may increase thesurface area of the food sample and cause it to better mix with thein-flowing process liquid. In some embodiments, the surface of grinder3724 can be textured in a way that facilitates the grinding, crushing,or mixing of the food sample. A textured surface may be, for example, aroughed surface or a surface with a plurality of spikes.

During the grinding stage, in food chamber 3716, the process liquid mayinteract with the food sample to generate a processed food mixture. Thisinteraction may extract an ingredient of the interest from the foodsample to generate a mixture of the process liquid and that ingredient.For example, when the ingredient of interest in a gluten protein, theprocess liquid may include alcohol (e.g., it can be an aqueous solutionof alcohol). The alcohol in the process liquid can dissolve at least aportion of gluten in the food sample, thereby generating a processedfood mixture that contains gluten. The processed food mixture may have aliquid part, called the processed food liquid, which can flow throughprocessed liquid channel 3717. The processing liquid may dissolve thefood sample in full and create a solution. In this case, the processedfood liquid may be all or part of the resulting solution, which flowsthrough processed liquid channel 3717. The processing liquid may alsodissolve the food sample in part and create a sold-liquid mixture. Inthis case, the processed food liquid may be some or all of the liquidpart in the mixture, which flows out of food chamber 3716 and throughprocessed liquid channel 3717.

After the grinding and mixing stage, the processed food liquid can flowout of food processor 3700 through exit port 3718. The processed foodliquid may, for example, enter a cartridge. In some embodiments, thecartridge may have an input port coupled to exit port 3718 of foodprocessor 3700. The cartridge may, for example, be configured to detecta protein such as gluten.

Food processor 3700 may have a variety of sizes. By way of example, insome embodiments, body 3710 may have a length (L1) in a range of, e.g.,about 0.75″ to about 1.25,″ a width (W1) in a range of, e.g., about 0.5″to about 0.75,″ and a height (H1) in a range of, e.g., about 0.2″ toabout 0.3.″ Arm 3720 may have a length (L2) in a range of, e.g., about1″ to about 1.25.″.

FIGS. 38A-38E show five examples of processing and detection system s3800, 3850, 3860, 3870, and 3880 for food samples according to differentembodiments. Systems s 3800, 3850, 3860, 3870, and 3880 each include afood processor 3810 and a cartridge 3820. Food processor 3810 isconfigured to receive a food sample, have it interact with a processliquid, and extract a processed food liquid, e.g., liquid 3830,resulting from the interaction. In processing and detection system 3860and 3870, on the other hand, food processor 3810 is similar to foodprocessor 3700 of FIG. 37. The food processor may also be of otherforms.

In each system, cartridge 3820 is configured to receive processed foodliquid (e.g., liquid 3830) and detect the presence of molecule ofinterest. In some embodiments, cartridge 3820 includes at least onesensor that performs the detection. Further, in some embodiments,cartridge 3820 also includes an input port that is coupled to an outputport of food processor 3810 to receive the processed food liquid.

In various embodiment, cartridge 3820 may be similar to one or more ofthe cartridges discussed above. In some embodiments, cartridge 3820detects presence of at least one gluten protein in the processed foodliquid. In some embodiments, cartridge 3820 generates at least oneelectrical signal that indicates the presence of the molecule, e.g., atleast gluten protein. In some embodiments, the electrical signal mayalso indicate other information, such as the amount of the molecule,e.g., its concentration.

Systems 3850 and 3860 of FIGS. 38B and 38C further include an analyzer3840. In system 3870, the analyzer may be part of cartridge 3820.Analyzer 3840 may be configured to receive the electrical signalgenerated by the cartridge, analyze the signal to determine the presenceof the molecule of interest, and further display the results on adisplay 3842. In some embodiments, the analyzer may further determinefrom the electrical signal other information, e.g., the concentration ofthe molecule, and show that information on display 3842.

In various embodiments, a processing and detection system may be packedand distributed as one unit, or may be packed and distributed inseparate sub-units. In some embodiments, for example, two or more of thefood process, the cartridge and the analyzer may be included in onepackage. In some other embodiments, the cartridge and the analyzer maybe included in one package that is separate from the food processor. Thefood processor may be, for example, disposable. The system may use adisposable food processor for one or a few times of detection, beforereplacing the food processor with a new food processor. Each foodprocessor can function with the same cartridge. In some embodiments, oneor more of the used food processors are configured such that the exitport for each of them can couple to an input port in the cartridge. Insome embodiments, the exit port and input port can couple if one of themcan fit into the other.

It should be understood that the principles of operation of variousembodiments of the wearable device discussed above can also beimplemented in a system that is not wearable. For example, the analyzercan be implemented as a desktop device that can receive cartridgesaccording to the present teachings for detecting, and optionallyquantifying, an analyte of interest, e.g., a gluten protein, in a foodsample.

Further examples are provided in the Appendices for further illustrationof various aspects of the present teachings and to show the feasibilityof implementing the teachings of the disclosure. These examples areprovided only for illustrative purposes and are not intended to presentnecessarily the optimal ways of practicing the teachings of thedisclosure or optimal results that can be obtained.

While several exemplary embodiments and features are described here,modifications, adaptations, and other implementations may be possible,without departing from the spirit and scope of the embodiments.Accordingly, unless explicitly stated otherwise, the descriptions relateto one or more embodiments and should not be construed to limit theembodiments as a whole. This is true regardless of whether or not thedisclosure states that a feature is related to “a,” “the,” “one,” “oneor more,” “some,” or “various” embodiments. Instead, the proper scope ofthe embodiments is defined by the appended claims. Further, stating thata feature may exist or can exist indicates that the feature exists inone or more embodiments.

E. EXPERIMENTAL RESULTS FOR SOME EMBODIMENTS

This section includes an explanation of experimental setups and resultsbased on some embodiments. Some embodiments use graphene. The honey comblattice structure of this material enables functionalizing it withorganic materials such as antibodies to detect targeted materials. Someof the experiments demonstrated the ability to detect Gluten familyproteins by making graphene based sensor functionalized by antibody andtransient measurement of ohmic resistance of the sensor. The resultsshowed patterns of ohmic resistance by exposing the sensor to targetedprotein samples.

Experimental Setup and Procedures

Materials: 1 g of 1-pyrenebutanoic acid succinimidyl ester with 95%purity was purchased from Sigma-Aldrich. Sheets of 5 cm×10 cm monolayergraphene coated PET were ordered from ACS materials and sliced intosquares of 1 cm length. The mouse monoclonal [14D5] to Gliadin asAnti-Gliadin antibody [14D5] was purchased at the batches of 100 μg withconcentrations of 1 mg/ml. Also anti-mouse IgG monoclonal [UPC-10](Mouse IgG2A isotype control) was ordered from Sigma-Aldrich in batchesof 1 mg, solution in 0.01 M phosphate buffered saline, pH 7.4,containing 1% bovine serum albumin and 15 mM sodium azide.

Sensor fabrication: Pieces of 1 cm by 1 cm of the coated PET sheets byCVD monolayer graphene were placed separately inside the Eppendorftubes. Each tube was then filled with Methanol and washed by water. Then1 ml of 5 mM 1-pyrenebutanoic acid succinimidyl ester indimethylformamide (DMF) was added to the tubes for 2 hrs at roomtemperature. Tubes were washed after wards with pure DMF and later withDI water. Tubes were incubated with 5 μg/ml of Anti-Gluten antibody inSodium Carbonate buffer, pH 9.0, overnight at 4 degrees. In the nextmorning the chips were rinsed with DI water and PBS. Tubes then filledwith 0.1M Ethanolamine pH 9.0 and chips left for incubation for 1 hr atroom temperature. Then, they were rinsed with 0.1% Tween 20 solution.The chips then were incubated in 0.1% Tween 20 solution for 1 hr at roomtemperature to passivate uncoated graphene area. After incubation withTween 20, the tubes were filled with TBST+0.5% BSA (BLOCKING BUFFER) andleft for 1 hr at room temperature. All chips then were rinsed by PBS andDI water and dried slowly in room temperature. The same protocol wasapplied for fabrication of sensors functionalized by anti-mouse IgG andIgM antibody.

Spectrophotometry: The untreated chips were conjugated to HRP (1:2500dilution) for 1 hr at room temperature, and then were washed by TBST 4times. Then HRP was added to substrate's tube an allowed to develop for5 minutes. The chips and sample then were read for A450 onspectrophotometer.

Galvanometric measurements: Two droplets of high conductive silver gluewere placed on the corners of the chips and let them dry in roomtemperature for at least half an hour up to 2 hrs. The functionalizedchips then were located separately on probe station connected to Agilent34401A multimeter setup for measuring transient resistant over time. Themultimeter was connected to a laptop for recording the data. Differentsamples of Gluten solutions with different concentration were studiedand the transient sensors' resistant were recorded.

Experimental Results

Spectrophotometry: The first test was to determine if an mAb could becovalently linked to a graphene-coated chip. To accomplish this, anHRP-conjugated antibody was linked to a graphene-coated chip which couldbe detected colorimetrically if bound. The test was positive, indicatingthat the HRP-labeled mAb was bound to the chip.

Next experiment tried to demonstrate that the Abcam anti-gliadin mAbcould be bound to a graphene-coated chip. Since the Abcam mAb is notlabeled, but binds gliadin, the gliadin was conjugated to biotin so itcould be detected by HRP-conjugated streptavidin (which bindsspecifically to biotin). So, the anti-gliadin mAb was linked covalentlyto the graphene-coated chips or just allowed to bind the chip withoutcrosslinking. If the mAb was bound, it would bind the biotinyltedgliadin, which in turn would bind the HRP-streptavidin and there wouldbe a detectable color. The results are shown in FIG. 39, which showssome experimental results related to Anti-Gliadin mAb linkage tographene-coated chips according to an embodiment. In the experiments,covalent linkage showed more intense color than simple adherence withoutlinkage. Chips without antibody were negative in this study. One mayconclude that mAb specifically recognizes the biotinylated-gliadin.

Next experiment attempted to study the effect of ethanol concentrationon reaction, since the gliadin is extracted in ethanol. A challenge isthat gliadin does not readily dissolve in ethanol. A 1 mg/ml solutionwas attemoted in 70% ethanol only to achieve a turbid suspension, evenafter sonication. Filtering removed the turbidity but also a significantamount of the gliadin. Anti-gliadin-bound ELISA plates were used forthis test. The results are shown in FIGS. 40A and 40B, which demonstrateeffect of Biotinylated-Gliadin Binding at Different Concentrations ofEthanol according to an embodiment. In this experiment, the turbidgliadin signal was stronger than the filtered gliadin in all casestested. The mouse IgG2a isotype control did bind gliadin, but the turbidgliadin did stick to it, indicting a significant amount of non-specificbinding was occurring. The amount of gliadin being used appears to be invast excess. Also, 50% ethanol yielded a stronger signal than the 70%ethanol indicating it could be affecting the binding of gliadin to theantibody.

In order to determine whether ethanol was adversely affecting theresults, a working concentration range for the gliadin was determined.The filtered biotinyated-gliadin solution was diluted from 1:10 using adilution factor of 10 to home in on a usable decade range (FIGS. 41A,41B) employing the mAb bound ELISA plates. FIGS. 41A and 41B illustrateresults of determining a working gliadin concentration range accordingto one embodiment. The usable range was between 1:1000 and 1:100,000.This range was narrowed further to between 1:4000 and 1:8000. 1:5000dilution was selected to be used going forward.

Then, the effect of ethanol concentration was examined in mAb boundELISA plates. Biotinylated-gliadin was diluted at 1:5000 in differentconcentrations of ethanol (0%, 9%, 18%, 35% and 70%) (FIGS. 42A-42B and43A-43B). FIGS. 42A-42B illustrate some effects of ethanol concentrationon gliadin binding according to some embodiments. FIGS. 43A-43B alsoillustrate some effects of ethanol concentration on gliadin binding fromdifferent perspectives according to some embodiments. In some cases, theassay does not work as well at 70% ethanol. 35% seems to provideacceptable results but there appear more non-specific binding on theisotype control mAb. In some embodiments, a suitable ethanolconcentration is between 10%-20%.

Next experiments tried the protocol out on the graphene-coated chipsusing 15% ethanol with 1:5000 dilution of gliadin. FIG. 44 shows resultsfor proof of concept according to an embodiment. More specifically, FIG.44 shows the protocol with different the pieces assembled: anti-gliadinmAb covalently linked to graphene-coated chips, reacted withbiotinylated-gliadin and detected with HRP-Streptavidin. In FIG. 44, theassay conditions were as follows: Antibody concentration: 3 ug/ml;Biotinylated-Gliadin dilution: 1:5000; Ethanol concentration: 15%;Streptavidin-HRP dilution: 1:5000; and Absorbance readout: 450 nm. Thetest was successful and specific. The final step to show proof ofconcept should be testing whether unlabeled gliadin can be detectedbinding to the graphene-coated chips with linked anti-gliadin mAb.

Galvanometric measurements: Some experiments studied effect ofanti-gliadin antibody on signal enhancement. The studies compared theresults of high concentrated gluten solutions on two sensor chip withfunctionalized antibody and untreated one. Some of the experimentalresults are shown in FIGS. 45A-48D.

FIGS. 45A-45B show the distinguished pattern between the treatedgraphene and untreated one according to one embodiment. Morespecifically, FIG. 45A shows the results for naked graphene sensor,while FIG. 45B shows the results for a graphene sensor functionalized byanti-gluten antibody. For untreated graphene, the signal of resistanceis similar to a ramp shape that gradually increases. For the treatedsurface, on the other hand, the signal change has a form that resemblesa step function. The results indicate enhancing effect of glutendetection by functionalizing the graphene with antibody.

Further experiments showed the consistency of patterns in both cases andaccording to some embodiments. FIGS. 46A-46B, for example, compare theresults for sensors functionalized with anti-gliadin antibody and thosefunctionalized with mouse monoclonal IgG antibody, according to oneembodiment. More specifically, FIG. 46A shows sensor behaviorfunctionalized by mouse IgG control antibody, and exposed to high dosageof Gluten. FIG, 46B, on the other hand, is similar to FIG. 45B and showssensor behavior functionalized by anti-Gluten antibody and exposed tohigh dosage of Gluten. FIGS. 46A and 46B show a pattern of resistancechange that is similar to the one discussed above, in exposure to highdosage of gluten in alcohol samples. One different is that, according tothese results, when using anti-gliadin antibody, the signal is about 10%stronger than the other cases.

Further studies showed that solutions without gliadin content havedifferent resistant pattern as compared to those with the gliadinsolutions. FIG. 47A shows ohmic behavior of a sensor functionalized byanti-Gluten antibody, and exposed to none-Gluten solution according toan embodiment. FIG. 47B, on the other hand, shows ohmic behavior of asensor covered with Tween 20 and exposed high dosage of Gluten accordingto an embodiment. FIGS. 47A and 47B indicate distinct patterns in thetwo cases.

As seen in FIG. 47B, some embodiments studied the effect of Tween 20 topassivate the graphene surface, by treating the surface area of thesensor with Tween 20 only and without functionalizing it by any type ofantibodies. The resistant measurements showed no changes in sensorresistance in experimental time when the sensor was exposed to thegliadin solution sample.

FIG. 48A-48D show results of experiments that studied the effect ofgliadin concentration on functionality of the antibody in the sensoraccording to an embodiment. More specifically, FIG. 48A shows the ohmicbehavior of a sensor functionalized by mouse IgG control antibody,exposed to diluted gluten-alcohol solution; FIG. 48B shows the ohmicbehavior of a sensor functionalized by mouse IgG control antibody,exposed to concentrated gluten-alcohol solution; FIG. 48C shows theohmic behavior of a sensor functionalized by anti-Gluten antibody,exposed to diluted gluten-alcohol solution; and FIG. 48D shows the ohmicbehavior of a sensor functionalized by anti-Gluten antibody, exposed toconcentrated gluten-alcohol solution. In these experiments, twoconcentration of gliadin protein in alcohol were chosen for this study.The concentration effects then were studied on the graphene surfacesfunctionalized with anti-gliadin antibody and also with mouse IgGantibody as the control. The results showed the same electricalresistance pattern for both substrates when they were exposed to highdosage of antibodies.

On the other hand in a much diluted concentrations only anti-gliadinantibodies were responsible to enhance the signal. This study showedthat the Abcam anti-Gliadin antibodies are able to attached to graphenesubstrate through the linkers and keep their functionality. Also studiesshowed functionalizing the graphene with antibody can enhance the signalcapturing and also enhance detection of low concentration of gliadinproteins in the samples.

In some embodiments, a sensor according to the present teachings caninclude a graphene layer functionalized with an agent that is capable ofinteracting, e.g., binding, with one or more pathogens, e.g., microbialpathogens. The binding of one or more pathogens to such a functionalizedgraphene layer can change at least one electrical property of theunderlying graphene layer, e.g., its electrical conductance. Such achange in the electrical conductance of the graphene layer can in turnbe detected, e.g., in a manner discussed above, and can be correlatedwith the presence of the pathogen(s) in a sample under study.

By way of example, FIG. 49 schematically depicts such a sensor 4000,which includes an underlying substrate 4002, e.g., a silicon substrate,on which a graphene layer 4004 is disposed. In this embodiment, apathogen-binding agent 4006 in the form of a recombinant protein, whichis described in more detail below, is coupled to the graphene layer viaa linker 4008. A variety of linkers, such as those discussed above, canbe utilized.

In this embodiment, the recombinant protein is a genetically engineeredversion of human mannose-binding lectin (MBL) that is capable of bindingto a wide variety of pathogens. The engineered MBL protein can begenerated by deleting the collagen-helix domain of 650 kDa native humanMBL protein and fusing the remaining carbohydrate-recognition domain andneck domains of the MBL protein to human IgG1-Fc. Further detailsregarding the Fc-containing MBL can be found in the followingpublications, each of which is herein incorporated by reference in itsentirety: U.S. Patent Application No. 2014/0220617 entitled “DialysisLike Therapeutic (DLT) Device,” and an article titled “An extracorporealblood-cleansing device for sepsis therapy,” published in Nature Medicinein 2014, and an article entitled “Improved treatment of systemic bloodinfections using antibiotics with extracorporeal opsoninhemoadsorption,” published in Biomaterials 67 (2015) 382-392.

A sensor according to the present teachings can detect a variety ofpathogens, such as gram-negative and gram-positive bacteria, yeasts andfungi. Some examples include, without limitation, Escherichia Coli(E-Coli), Staphylococcus aureus, Listeria, etc.

FIGS. 50A and 50B schematically depict an example of a device 5000according to an embodiment of the present teachings that includes asensor similar to that described above and shown in FIG. 49. The device5000 includes a substrate 5002 on a top surface of which a layer ofgraphene 5004 is deposited. A variety of different substrates can beemployed. By way of example, the substrate 5002 can be any of asemiconductor, such as silicon, or glass.

Two metallic pads 5005, 5006 in electrical contact with the graphenelayer 5004 allow measuring the electrical resistance of the graphenelayer, and particularly, a change in the electrical resistance of thegraphene layer in response to exposure thereof to a sample containing apathogen of interest. In some embodiments, the electrically conductivepads can be formed of silver high conductive paste, though otherelectrically conductive materials can also be employed. The conductivepads can be electrically connected to a measurement device, e.g., avoltmeter, via a plurality of conductive wires for measuring the Ohmicelectrical resistance of the graphene layer.

The device 5000 further includes a microfluidic structure 5008 havingtwo reservoirs 5008 a/5008 b and a fluid channel 5008 c that fluidlyconnects the two reservoirs. As shown more clearly in FIG. 50B, thefluid channel can be arranged such that a portion thereof is in fluidcontact with a portion of the graphene layer 5004.

In some embodiments, in use, a sample suspected of containing a pathogenof interest can be introduced into one of the reservoirs 5008 a, 5008 band can be made to flow, e.g., via application of hydrodynamic pressurethereto, to the other reservoir through the microfluidic channel 5008 c.The passage of the sample through the channel 5008 c brings the sampleinto contact with the functionalized graphene 5004. Without beinglimited to any particular theory, the interaction of the pathogen ofinterest with proteins to which it can bind can mediate a change in theelectrical conductivity (and hence resistance) of the underlyinggraphene layer 5004, e.g., via charge transfer or other mechanisms. Thischange in the electrical conductivity of the graphene layer 5004 can inturn be measured to detect the presence of the pathogen of interest inthe sample under study.

As shown schematically in FIG. 51, in some embodiments, the device 5000according to an embodiment can include a reference electrode 5101disposed in proximity of a functionalized graphene layer 5004, e.g., ata distance in a range of about 50 micrometers to about a few millimeters(e.g., 1-2 millimeters) above the functionalized graphene layer. Thereference electrode can be utilized to generate a time-varying electricfield at the interface of the functionalized graphene layer and theliquid in contact with that layer. For example, in this embodiment, anAC voltage source 5102 can be employed to apply an AC voltage to thereference electrode 5101, which can in turn result in the generation ofa time-varying electric field in the space between the referenceelectrode and the functionalized graphene layer 5004.

The application of a such a time-varying electric field to the interfacebetween the graphene layer 5004 and the liquid in contact with thegraphene layer can advantageously facilitate the detection of one ormore electrical properties of the functionalized graphene layer, e.g., achange in its resistance in response to its interaction with a pathogenof interest exhibiting preferential binding to the protein of thefunctionalized graphene layer. In particular, it has been discoveredthat the application of an AC voltage having a frequency in a range ofabout 1 kHz to about 1 MHz, e.g., in a range of about 10 kHz to about500 kHz, or in a range of about 20 kHz to about 400 kHz, or in a rangeof about 30 kHz to about 300 kHz, or in a range of about 40 kHz to about200 kHz, can be especially advantageous in this regard. By way ofexample, the amplitude of the AC voltage applied to the referenceelectrode can be in a range of about 1 millivolt to about 3 volts, e.g.,in a range of about 100 millivolts to about 2 volts, or in range ofabout 200 millivolts to about 1 volts, or in range of about 300millivolts to about 1 volt, e.g., in a range of about 0.5 volts to 1volt. Further, in some cases, the voltage applied to the referenceelectrode can have an AC component and a DC offset, where the DC offsetcan be in a range of about −40 volts to about +40 volts, e.g., −1 voltto about +1 volt.

Without being limited to any particular theory, in some embodiments, itis expected that the application of a such a voltage to the referenceelectrode can minimize, and preferably eliminate, an effectivecapacitance associated with a sample, e.g., a liquid sample, with whichthe functionalized graphene layer is brought into contact as the sampleis being tested, thereby facilitating the detection of a change in theresistance of the underlying graphene layer in response to theinteraction of the protein with a respective pathogen. In some cases,the effective capacitance of the sample can be due to ions present inthe sample.

F. CONCLUSION

In this disclosure the following qualifications apply, unless statedotherwise or deducted otherwise from the context. The terms “include,”“comprise,” “contain,” and “have,” when used after a set or a system,mean an open inclusion and do not exclude addition of other,non-enumerated, members to the set or to the system. Further, theconjunction “or” is used not exclusively but inclusively to mean and/or.Moreover, a subset of a set may include one or more than one, includingall, members of the set. Also, the qualifier “some” may refer to asubset of a set that, therefore, may sometimes include all members ofthe set.

The foregoing description of the embodiments has been presented forpurposes of illustration only. It is not exhaustive and does not limitthe embodiments to the precise form disclosed. Those skilled in the artwill appreciate from the foregoing description that modifications andvariations are possible in light of the above teachings or may beacquired from practicing the embodiments. For example, the describedsteps need not be performed in the same sequence discussed or with thesame degree of separation. Likewise various steps may be omitted,repeated, combined, or performed in parallel, as necessary, to achievethe same or similar objectives. Similarly, the described systems neednot necessarily include all parts described in the embodiments, or mayinclude multiple number of the described parts or other parts that arenot described. Moreover, some parts of a system may perform tasks thatare here described as being performed by one or more other parts.Accordingly, the embodiments are not limited to the above-describeddetails, but instead are defined by the appended claims in light oftheir full scope of equivalents.

1. A sensor, comprising: a substrate, a graphene layer disposed on asurface of said substrate, a protein bound to said graphene layer,wherein said protein is capable of binding to one or more pathogens, andwherein the binding of the protein to said one or more pathogensgenerate a change in an electrical property of the graphene layer. 2.The sensor of claim 1, wherein said protein is a recombinant protein. 3.The sensor of claim 1, further comprising a linker for attaching saidprotein to said graphene layer.
 4. The sensor of claim 1, wherein saidelectrical property is electrical conductance of the graphene layer. 5.The sensor of claim 1, wherein said protein is capable of binding to anyof a gram-negative, gram-positive bacteria and fungi.
 6. The sensor ofclaim 5, wherein the gram-negative, gram-positive bacteria and fungiinclude any of Escherichia Coli (E-Coli), Staphylococcus aureus, andListera.
 7. The sensor of claim 1, wherein the substrate is asemiconductor.
 8. The sensor of claim 6, wherein the substrate issilicon.
 9. The sensor of claim 1, wherein the protein is covalentlybound to the graphene layer.
 10. The sensor of claim 1, wherein theprotein is a version of human mannose-binding lectin (MBL).
 11. Thesensor of claim 1, further comprising a microfluidic delivery devicecoupled to the graphene layer for delivery of a fluid sample thereto.12. The sensor of claim 11, wherein the microfluidic delivery deviceincludes two fluid reservoirs and a fluid channel connecting said tworeservoirs, wherein said fluid channel is configured such that at leasta portion thereof is in fluid contact with at least a portion of thegraphene layer.
 13. The sensor of claim 1, further comprising areference electrode disposed in proximity to the graphene layer.
 14. Thesensor of claim 13, further comprising an AC voltage source for applyingan AC voltage to said reference electrode.
 15. The sensor of claim 14,wherein said AC voltage source is configured to apply an AC voltagehaving a frequency in a range of about 1 kHz to about 1 MHz.
 16. Thesensor of claim 14, wherein said AC voltage has an amplitude in a rangeof about 1 millivolts to about 3 volts.
 17. A method of detecting apathogen in a sample, comprising: bringing a sample into contact with agraphene layer functionalized with a protein exhibiting preferentialbinding to a pathogen, applying a time-varying electric field to saidfunctionalized graphene layer, monitoring electrical resistance of saidgraphene layer in response to interaction with said sample, anddetecting presence of said pathogen in said sample by detecting a changein said electrical resistance indicative of interaction of said pathogenwith said functionalized graphene layer.
 18. The method of claim 17,wherein bringing the sample into contact with the graphene layerincludes delivering sample through a microfluidic structure, saidmicrofluidic structure having at least one reservoir and a fluidicchannel fluidly coupled to said reservoir, said fluid channel being influid communication with at least a portion of said graphene layer, andsaid reservoir being configured for receiving a sample.
 19. The methodof claim 17, wherein monitoring electrical resistance of the graphenelayer in response to interaction with the sample includes measuringelectrical resistance of the graphene layer using a pair of conductivepads that are electrically coupled to the graphene layer.
 20. The methodof claim 17, further comprising distinguishing the pathogen of interestfrom among a plurality of pathogens of interest in the sample based on atemporal profile of modulation of electrical resistance of the graphenelayer.
 21. The method of claim 17, wherein said pathogen comprises anyof chlamydia trachomatis and Neisseria gonorrhoeae.